A-rig arm length and bend amount, blade size

I fish a fair bit with an A-rig, but I still have lots of questions:

1) Is there a useful difference between the 6.5 and 5.5 arm lengths? A couple of my a-rigs have the shorter length. 

2) I also have some "mini" a-rigs, but I never really saw a situation where I thought to myself "you should throw that"

3) I've been using a gentle curve/bend to get to almost 90 degrees. Makes for a nice big presentation. Is that really the right bend? All of the storage options I've found so far crank it back down so far I worry about the wires. So I started wondering if I'm over-doing it. Each of the Plano a-rig box, TW tubes, red ones that slide over, etc all seem to really put load in the exact opposite direction which seems like a bad idea. 

4) some of these rigs have small blades (6th sense, stealth rig, most of them), some have big blades (Shane's moneyball) - I think I know when to throw the no-blades, but small vs large? Again, make enough difference to specifically choose one over the other? 

Thanks in advance!