Hello Hudson,
Regarding the BVM5012, I have the same unit but have not run it yet. I asked here on RCU for any member's with first hand experience using this unit and didn't really get anywhere. There is however a thread or two on RC Groups that mention the 5012 suitability on 10S /11S/12S. From what I understand the early 5012's were designed and manufactured with the battery tech of the time. That is 25 to 30C Lipos. Since Battery technology has evolved, Lipo performance and battery voltage sag has reduced.
Considering the above, if your 5012 has a 110A ESC, then the ESC may fail when using current Lipo tech (70C) at 12S.
When I finally get around to using my unit I was either going to run it on 10S with the standard 110A ESC, however if I was going to run 12S I would definitely swap out to a higher amp ESC.
In my opinion, the BVM T-33 is already loaded heavily enough, so any opportunity to reduce wing-loading is a good one. Even the 10S system will have more thrust than what the ICDF ever had. Obviously battery weight would be greater than 22oz of glo fuel, but EDF performance on 10S will be better than any BVM91/96.
Good Luck!
Keep Posting, thanks, Frank