I'd set your seat like this: center of front of seat 5/8" left of steering upright, RR strut 4" from motor rail, front of seat 1/4" from touching steering upright, top of seat 8.75" from top of axle.
I'd run both caster blocks back and start with a baseline like this: 46.5% nose, 59.5-61.0% left (adjust according to bite), 65.0% cross, +0.25 LF camber, -3.25 RF camber, 6 deg LF caster, 8 deg RF caster, 1.5" front stagger, 1" rear stagger (more for small tracks, less for big), 38.75-39.0" rear track width (RR rim 3/16" from frame rail).
Good luck!
James