Absolutely perfect for 18mm DD, thank you! As a bonus I can also use it for a 54mm zipperless pancake bay.
I've been working on 18 mm motors and the largest has 10" of propellant. D grain with 3.5 sec burn, an F23-10.Current rough sims put it between 6-9k ft. Depends on if I go minimum or subminimum and how long I end up making it.