I was WRONG. They looked the same size as the old REAR shocks...Problem solved. Checked with Rancho sizes and measured the ones that came off (what I should have done in the first place) and came up with RS5118s for the rear (what they told me I needed for the front) and RS5151s for the front.
After that fiasco, I realized ANOTHER thing I should have made sure I got from the 'burban--the rear U-joint straps. OOPS! That was fun finding those. Got a Moog set from NAPA. AND---I had both the Precision 447 U-joint and the Precision 348 (concluding that the 348 was the correct fit and hadn't taken back the 447 yet), and, without paying attention, installed the 447 u-joint--a perfect fit. I guess that means my driveline is actually 3R....???? Not that it really matters--I know what works...
Anyway, I got my U-bolts and plates from Off-Road design and got those in lickedy-split after finagling to get the rear end up and into place myself. I found that it was easier to do raising one side at a time.
After all that was done, I hooked up the brake lines (perfect match), connected the breather hoses, torqued everything down, zip-tied all of the e-brake cables out of the way (I'll deal with them in the spring), and put the tires back on the beast. First drive was excellent, except that I needed an alignment REALLY BAD.

That was what I did yesterday. I also wasn't ready for how high she was going to rev on the highway. There maybe a TH700R4 swap in my future....
I'll post pics in the next couple of days and try to write up a summary of the experience with lessons learned. I also found a great video on Youtube that I wish I had found weeks ago that I will link to as well...Thanks for all the help from everyone!! Now on to my Gen 2 issues....