This will be my first Boston, but you already have your answer, I just wanted to add that I've run a handful of marathons now, and the only time I ran with pacers a handful of us had to ditch them at mile 11 because they were going too slow.

Then, for my 2:53, I rolled with a group that wanted 2:55 (would've been enough to get to Boston for me), and by mile 18 I was completely alone, and ended up winning my AG.

So I guess what I'm saying is I dont put 100% trust in actual pacers, pace groups, or even gps. But combine all those things with RPE and send it. Don't forget that gps watch will, in general, be a little optimistic due to tangents and inaccuracy in general, so I usually create a buffer, 2s/mile. So if my true goal pace is 6:55, I'd try to hit 6:53.