65 barracuda mini tub where to start?

So i'm looking to mini tub my dart with a triangulated 4 link setup. What i got the car with was extra long leaf springs, some nasty looking slapper bars, and a pair of thrown in coil overs lol. It rides terrible and looks like crap too. It does have an 8 3/4 with 3.55 suregrip already in it. I want to mini tub my car but im not sure where to start. I have an extra 8 3/4 housing i can start getting ready. How short should i cut the housing? Im getting new end caps, and i was looking at Moser axles. One set they make is 28" long, and the other is 27 11/16''. Can i assume i will need the shorter ones?