Outdoors I wouldn't recommend total length, (vbars/stab), more than 28-30". Indoors is what you feel comfortable with. I would guess the minimum length isn't as big of an issue as maximum.
Sights are like buying safes. Don't buy what you need right now, but for what you'll need in the future. Sure-Loc, Shibuya will both do what you like. I do like my Sure-Locs, and they've got incredible reliability, and if you have problems, the company will make it right.I will do 3D shoots and 900 will that make a difference in length of stabilizer i use? Since I am just getting into this what is a good starter Sight?