Have a couple questions about Butt Rib attachments for a Speedster (Classic Mod 4) ... #1: should there be any gap between Rib #1 & the Butt Rib & if so, how much of a gap should it be?? #2: I'm assuming the Butt Rib should be centered on Rib #1 ??? - I'm working from a build manual that's from the 90's & is in poor shape (coffee marks / glue / missing information / etc) Thanks in Advance!!

John