I wouldn't be too worried about what motor to use until I was ready to build and fly it. You need a LOT more experience and maturity before a project like this......
Well said.
I think a more reasonable sized two stage project is a better approach, I think you would want to master the basics of successful two stage ignition with composite motors first - things can go bad very quickly on a high power two stage flight, and the bigger it is, the more there is to be concerned about.
There are some very good two stage flyers on this Forum...pretty sure they all started with a smaller scale project first.
I'm nowhere near their skill level.....I started with a Cosmodrome Aerobee - Hi......a very cool kit and a very instructive build.
You'll save yourself some time and money going with that - or another good two stage kit....rather than scratch building a larger one as your first foray into it.
With the altitudes you'll get....need to master the dual deployment methods - prior to that.
I believe I recall the 4 inch Wac Corporal two stage project that wadavidson mentioned in his post, - it was a demo/test before they went to the larger one (Damien Ruso and Bill Davidson "Team Wac Corporal/Garden State Tripoli").
High Power Rocketry mentioned that 4 inch Wac project and I believe it was an I to an H flight, as he said.
Before they did their "dream project" (a full size two stage Wac C) - they "did their homework".
After a couple of two stage flights on smaller scale stuff, I built a 4 inch diameter two stage Wac Corporal in the same configuration....38 mm for I to H fights. And only after a couple of smaller projects.
I can tell you a scale looking interstage on a two stage Wac C. is a design challenge.
And that interstage has to be structurally sound. As solid as I made mine - I'm still not satisfied with it.
