Wow, You are into the serious performers, In grammar school I used to build the little ones, mostly Estes, and launch those, still big fun but not as big as your rockets, About 12 years ago I built a Carde Black Brant, It's sitting on my shelf now, never sent it up but I still have the engines for it.
My buddy and I thought about building one about the same size as the one in your picture but we never got off the launch pad(pun intended)