epitrochoid

I see these different categories of wheels from different manufacturers. Looking at the RH CX's, hart recommends a +42 low disk offset for the rear and +32 low disk in the front (19 X 8.5/9.5). For the rear, it gives a 60mm rear lip which is cool.

http://www.hartwheels.co.jp/cat_0312...ypecx_spec.htm

i'm not real familiar with the whole disk thing, but i noticed that with mid, high, super high disks, is the lip is sacrificed with equal offsets. is that in interest of say larger calipers? so my question then is, if the low disk clears the OEM calipers, how much extra room would i need if i wanted to go with a BBK in the future?

we're obviously talking about special order offsets here, but my goal would be to maximize the lip with just enough clearance for a BBK.