Scratchbuilding A Booster Frame

I did a 3D CAD (SolidWorks) Model of the Booster Frame with your plan, thanks for it!

But I adjusted the base of the frame to the booster pipe, like in Vince’s Awesome reference pictures:

http://www.gb … =2&t=22743

I uploaded the CAD model in a dropbox:

and to GrabCad:

https://grabcad.com/library/ghostbuster … er-frame-1

Question: I think the first gap in the original picture looks smaller (top, right pic). Is it maybe less than 1" ?

Since making my booster frame I’ve found out from direct measurements of the hero that it should be a bit under 6" high so a smaller top section wouldn’t be inaccurate.