5 or 6 lug? Backspacing?

[au03z71]

I've got my bags and everything suspension wise and I'm looking at running some 20's or maybe 22's on my 72 and want to also do a disk brake upgrade. Should I go with 5 or 6 lugs? Is there a kit that anyone recommends? Also, what backspacing should I run to stagger the lips of my rims (larger lip in the back, smaller in the front)? Could I acquire this stance by running different width rims?

Sorry for the bombardment of questions... If anyone has input I'd appreciate it...

Thanks