I used 5/8" baltic birch plywood.
To cut one rocket section:
Cut bottom indexing holes in bottom section through material into waste board. Insert wooden dowels. Cut the rest of the file as assigned in CC. Move piece so upper set of holes is now aligned with holes cut through waste board. Cut upper section as assigned in CC. If I was doing it again, I would add pockets to align the braces/safety bars.
Flip everything and cut a second rocket section.
I used 2"x15" of the same plywood and pocket holes for braces/safety bars - one on leg not used for foot shelf and two towards the top. Foot shelf was 4.5"x15.5", main shelf was 12.5"x15.5". Use the holes in the shelf slots to mark positions for #8 threaded inserts in the main shelf to make it repositionably fastened to the sides.
Exhaust flame cut from fluorescent pink acrylic. I cut mine on my laser, but cutrocket wouldn't let me upload an .svg so I added it as a .c2d. Could be done on CNC also. I glued mine in, but you could add holes to screw it in.