15 X 7 with 3.75 b.s. rear. 15X7 with 4.125 b.s. front. I had the standard 3.75 b.s. on the front too, until I switched to Wilwood front disks, which moved the old wheels out far enough to hit the wheel wells.
Regarding tires. I took my car to a friends garage to mount the tires and he suggested 205 60 15 tires. Those are smaller than what I had in mind, but I DID want to have the same tires on all 4 corners. There just isn't a whole lotta room in the front. My car has been lowered 1 inch with mid-eye springs in back and the control arm relocation + aftermarket GT style springs in front. That's obviously part of the problem...BUT even after rolling my front fender lips I am still VERY close in front. Especially on the driver's side. The close spot is at 9:00 during hard left hand turns, when hitting a bump. In other words, the spring compresses, the wheel is turned and the tire is very close to hitting the fender down at the bottom. I don't really know why that is. Recently I had the fender off and when remounting it noted that the fender is about as far forward as it will go without elongating the slots under the hood. I would suspect a little bending of the unibody, BUT when I put an export brace on a couple of weeks back, it pretty much dropped onto all 12 bolts, meaning the shock towers are exactly where they are supposed to be!
Beats me. Anyway getting back to your project...I would go about it like this. Find a good tire store that doesn't sell the wheels. Ask them in advance if you can bring in some wheels for them to look at and mount on your car. Buy the wheels mailorder (from Summit maybe). Take 'em in and let them figure out what the biggest tire they can fit without rubbing is. If there is a problem then, they should make it right. If you tell them what will fit and there is a problem, you're stuck.