if your really good you could make it a 38mm mount then you could get up to a good size "I" motor. of couse i've seen a estes big daddy (stock size) called "K Daddy" fly on a k185..... id say it made 10,000 feet but thats just a guess.. imagine it on a k695r...... now were talking hyperspace.
With out a L1 cert. with the NAR or Tripoli, you can use up to a G. With a G64, it'll go maybe 3500-4000 ft. With a cert, you can use an H73 to an H242. I'm gonna estimate 5500-7000 ft. (I'm really not good at estimating)
modify it for 29 MM motors and fly it on an apogee F10 that will go for a REALLYlong time and I reccomend using a REALY long streamer(I mean 20 feet or more)
I just built a ROCKETPAD clone of the Estes"MAXI STREAK" & that flys with a "D" motor! Man it moves! With a D12-5 I lost it in the sky for a while but it was a bright YELLOW in color and I did pick it up a few hundred feet up on the way down with the 90" long streamer. The Maxi Streak is small-only about 13" in length with a bt-60 tube. It was fun & I got it back all three flights.
techman