RE: Viper Jet 2M Pointers/ tips.
Here is a 2M Viper that I am building for Jet Central. It has the New Jet Central Cheetah turbine.
I found that the tail cone set the pipe close the the bottom and some air gap at the top. I cut some cooling holes in the bottom of the fuse between the ventral fins.
I had a top half of a by-pass laying around so I fitted it.