I didn't have another .77 at the time to compare it to, but it appeared to me to run almost as good as the .91 that I had run in the same airframe.
At the very least, it's an option for you if you do have problems with the .77 carb, which you may not have. I had a .77 on a Byron fan in a Regal Eagle that I never had a problem with and I sold it after about 300 flights.

I have also read what you're saying about the loctite. I used it on every DF I ever owned, about 15 of them and some I flew for several years. I never had a problem related to head bolts. I used blue loctite on all the rest of the bolts, including screws in the retracts. I have seen DFs vibrate the screws out of a retract unit.