I've decided to calculate everything from scratch, rather than trying to adapt some other vehicle's springs. Then I'll order something - haven't decided to do coil-overs or keep the setup I've got. I've got the car garaged, and have started measuring things. Might take me awhile, but I'm happy to share what I come up with.
So far, the only hard data I have is that it weighs 2340 lbs, 1220 front & 1120 rear. I have about 3" of tire clearance at the top of the wheel well in the front, and 4-1/2" to the
oil pan drain plug (lowest point), so I don't think I will lower it any (nice to not scrape the curb going into my driveway)!
I'm looking for input, since this is all new to me - comments welcome!