I on my 30th consecutive 100+M week and have averaged 120M with mulitple 140+M weeks. I found that I improved rapidly initially but now my body is taking a while to get used to maintaining it - just coming out of a dip. What was previosuly said about the difference between doing for a short while and for an extended period is 100% true. But I am finally seeming to be getting to the point where this is "normal" to me.
My mistake was not keeping an eye on speed throughout - not enough strides or faster runs. I excused myself from it as I was pretty heavy when I restarted and thought it'd be too much for me with all the miles. When I progressed rapidly I got much faster but I'm still finding it very hard to run faster than 6mm pace - it's easy on the engine, but too tough for the chassis. I ran a 2:44 marathon 13 weeks in at only 75%maxHR, but could not have gone any faster. The speed will take a long time to come.
So, after 30 weeks of this, I'd say 120-140mpw is a great idea. But I'd add the following:
1) Keep some speed in there - not anaerobic work, but maybe some strides, some hill sprints and the odd tempo run.
2) I prefer a 14 or 15M and a slightly shorter 7M double than the 10/10. I find I get a better aerobic adaptation with the longer main run and the shorter double enables better recovery. I also prefer doing the main run first.
3) Apart from a few prescribed sessions (tempo, long run, strides) I have found that never pushing it and only going at the pace the legs want to go at is the recipe for keeping injury free. The speed will come from the prescibed runs and the other runs will pick up when they are good and ready. The one time I tried pushing it a bit more (as I felt I SHOULD be going faster with all these miles) I just set myself back a few months. Lack of patience, pure and simple. As a friend of mine told me, "Always protect what you have before reaching out for more".
4) If you can fit in stretching and strength work, then do it. Weak, inflexible legs struggle to go fast -I wish I'd got more done earlier. High mileage is a good excuse to skip that stuff, but I have found that those miles can mean that you need the supplementary training even more.
Just my experience. Hope it helps. Good luck!