Tomo, I went into 2006 Grandmas in 2:40 shape. I had run many race distances from 5K to the half suggesting I was in good enough shape to run a 2:40.
The summer of 2005 I trained specifically for shorter races and ran many PR's from 5K to the half. Low 16's and low 1:15 half. While training for the marathon I believe I ran about 27 even for a 5 miler and 34:25 for 10K.
So I think your fitness shows you are real close to 2:40. I also like all your long tempos with the M pace stuff mixed in. I did lots of that also.
Now 2006 Grandmas was HOT HOT HOT. I started the race knowing that 2:40 pace was really going to be rolling the dice, but after all my hard work was not willing to “settle” for a 2:45 pace run. Therefore I went out like any other day and ran 2:40 pace. I actually ran with the pack of women's elites for the first half. Me and the ladies 🙂
At half I could already tell I was toast. We went from a pack of 8 to immediately breaking up. Everyone strung out right then. I believe 1-2 of the women went on to finish at 2:40ish. A couple more DNF'd. I finished in a 2:47 low. I ran the last 10K the slowest I'd ever ran any 10K even a easy run in 8th grade. It was like 47 minutes or something crazy. I was probably on the verge of heat exhaustion if not worse.
So the question is then do you lock onto the 2:40 like I did or do you compensate if necessary? I don't wish I'd have done anything different. I would have been asking “what if” had I gone conservative in 2:45 pace from the gun.
Check out the above link. It explains very well why I added 7 minutes to my time on that hot day in 2006. Something for you to consider.
I think you are where you need to be. Go for it. I'll be there cheering 🙂