Interesting question. I’ve done some thinking about what amateurs can take away from Canova, partly just as a thought experiment, and here are some things that Canova says that I think are worth looking at with respect to the kind of question you're asking. The quotes below were collected from a document that somebody else compiled from Canova’s comments on a series of Letsrun threads. Thanks to that person and apologies for anything that I may have inadvertently misquoted. My comments are just that, my comments.
First, a caveat:
“A coach good for every athlete and for every kind of age and of value doesn't exist. I have problem, now, when I speak about the activity of very young people, and also when I speak about the activity of an amateur, because in my mind the normal level of talent, of training-sessions, of professionalism, and so of intensity in training, are very different from the level of basic activity, and it's not possible to do in miniature the same training of a champion for a normal athlete.
“Simply, they are two different things.”
That being said:
“Many of you look at training in the specific period of a season, and when the career is already well defined. Instead, the problem is to look at the beginning of their activity.
But the problem is: how we can prepare our body for working so hard in that direction ?
Under this point of view, an aerobic base is indispensable.
You must learn running very slow for running very fast.
But the real problem is: how much was the mileage and, better, what was the system of training when he was very young, in other words, how did he build his "aerobic house" ?
Every man needs from 10 to 12 years for building his "aerobic house". If you are Gebre, your house may be a skyscraper 60 floors high; if you are a non talented amateur, may be a small house of only 2 floors. But, in any case, you need more than 10 years for changing your attitudes, your physiology, your mind. After this period (I repeat, 10-12 years), also if you don't train more with big volume you don't lose your qualities, that are CONSOLIDATED.
When you arrive at that level, the best road is to reduce the volume of general training (that cannot give you any advantage, but can increase the wear and tear of your body and the risk of some injury) having the focus of improving yet a little in the volume of "specific training".
For example, speaking about a marathon runner, if you want to build your base for a big future race, and you are 18y old, you can increase your weekly mileage (connected with "general training") in this way (attention, is only an example) :
18 years : 60 miles (80% general + 20% specific)
19 years : 70 miles (80% + 20%)
20 years : 80 miles (80% + 20%)
21 years : 100 miles (75% + 25%)
22 years : 120 miles (75% + 25%)
23 years : 140 miles (75% + 25%)
24 years : 140 miles (70% + 30%)
25 years : 150 miles (70% + 30%)
26 years : 150 miles (65% + 35%)
27 years : 150 miles (60% + 40%)
28 years : 160 miles (60% + 40%)
29 years : 150 miles (55% + 45%)
30 years : 140 miles (50% + 50%)
32 years : 120 miles (40% + 60%)
35 years : 80 miles (20% + 80%)
We must look at the period good for putting hay in the farm, not at the period during which you use this hay.”
Note: Canova is talking about the development and career training arc of an elite athlete starting from the age of eighteen. That being said, I think the upshot for an amateur who wants to draw on Canova’s approach is that you should start by focusing on what Canova considers “general” training, which is primarily, though not exclusively, directed toward “building the aerobic house.” You can do a modest amount of what Canova considers “specific” training – i.e., what people are generally talking about when they talk about “Canova-style” training – but that shouldn’t be the main point of emphasis. Looking at the arc that Canova lays out, moreover, the initial progression appears to emphasize increasing the volume of training, not the proportional emphasis on “specific” training.
So, if the OP has been running 50 miles a week over course of the past year, the primary goal might be to run 60 miles a week over the next year, and 70 miles a week over the year after that, while doing some “specific” training but only as a distinctly secondary emphasis. (It’s not entirely clear what the %s mean, but I think it makes the most sense to look at them in terms of relative emphasis. So, over the course of those first three years, you would be 80% focused on “general” training and 20% focused on “specific” training.)
Of course, there’s a big difference between what this progression would look like for someone who is starting as an eighteen-year-old aspiring elite and someone who is starting as a mid-30s amateur! Those two paths are definitely going to diverge. Still, I think the underlying point holds: until you have fully “built your aerobic house" - something that most amateurs probably never do! - the most important and beneficial training is the “general” training that contributes toward that end. That being said, there will be a point in each training cycle where it makes sense to take the fitness you have been able to develop and sharpen it with an appropriate amount of “specific” training, and a similar point will probably come in your running career, too.
Finally, one more quote from this thread
https://www.letsrun.com/forum/flat_read.php?thread=3344054:
“Personally, I never met a scientist that was good coach, because they want to use athlete in function of training, not training in function of the athletes. Don’t forget that the most important problem to solve is to make easy what is difficult, and for this goal we need to be very simple, natural in our approach, bringing our athletes to train more without too much pressure from hard workouts. That’s the reason because too much hard training is a mistake, because athletics become a continuous examination, no more a pleasure. You can train hard preserving the ability of enjoying training, instead too many times athletes think that training is a must, and lose their nervous energies in fighting in training. Many runners leave good result in practice but have little energy for good result in races. Under this point of view, we have much to learn from African runners. When we are able to learn from them, we can teach our runners not to train too hard and have gas in the tank for races. I teach my runners that gas must be in the tank for you to drive the car. If the athlete is always taking gas from the tank then he will be on empty soon and not be able to run fast when it is the time to do so. That is why my training puts gas in the tank and progression is important. Yes, it is true that at the end of season my athletes use gas with ‘el medio’ workouts and other hard tempo tests. But it is after the gas tank is full that we can even start to think about this type of training.”