Can anyone with a Wilwood kit explain this

So I just decided to keep the SBP, upgrade to a 10 inch spindle and new spindle bolts on the front, and get the SSBC brake kit for the front. It has both bolt patterns, and both bolt sizes. Part of the problem for me with trying to go to BBP was that until I got the rear replaced, I was going to have to put an adapter on the back, which would have put the track width out 1.5 inches on each side, which would have completely knocked my wheel choices out of whack, and made it harder to deal with wheels when I did upgrade the rear. Of course now I'll probably be looking for a SBP rear when I do, and my wheel choices are limited, but it's all about a balance between functionality, what I can do now, and a little bit of 'does it still look good' :) Replacing the 9" spindle with the 10" was necessary because that's what the kit requires, plus I can use bigger bolts for the lower ball joint arm, which is nice, since rumor has it they are weak.