Two marathons, close together

I’m a HJ so take this for what it’s worth but I feel 2-3 weeks is too soon. I ran two last spring about 6 weeks apart and was fine. After the first marathon peaking at 70 mpw it took me about 3 weeks to feel strong in my runs again I took one week completely off then eased back into running. But at 6 weeks I felt really good and actually crushed the previous marathon time by several minutes. I went from 3:25 to 3:15. Far far slower than you but no matter how fast anyone is I feel recovery time is probably pretty constant.

If you are in 2:17:30-2:18:30 shape like you claim, then you don't need to ask this question. You have enough knowledge about running to know what you're doing.

If you are delusional about your current fitness, then you will end up being fairly disappointed.

Either way, 6 weeks is the answer here.

What gives you the impression you are in 217-218 shape? I‘m assuming you have a half result around 1:04.

Haven't actually gotten around to running a fast half yet. But my 15k (low 45) and 10 mile (48mid) are what I'm drawing 2:18ish type confidence from. Maybe 2:19 is more realistic for my first marathon cycle but certainly don't think 2:17 mid-high is crazy

Those are really good times for sure. It‘s always a little tough to know how that translates to distances 2.6 times longer.

I don‘t know if it‘s a great idea to do two marathons back-to-back when it‘s your first attempt. In particular, you mentioned it was a long, hard season. The strain of two marathons is quite the toll on the body.

I get the desire to win the first race in a tempo. but I’m sure you’ve won a race before with those times. Why not do a half six weeks before the goal marathon race?

What marathons are they?

6 weeks feels safest. If you're that fast I would think about just doing 1 of them.

If you're really going to run a controlled 2:30 then 3 weeks out could somewhat work in an intentional build up. No big taper for it, just a super light mid-week workout. Then take it easy until a good long run 2 weeks out with something like 2 x 5 or 6 miles thrown into an 18-20 miler.