Just as a follow up......
......I got tired of wrestling with the 38" SX's and took them up to my friendly neighborhood Goodyear tire store...
(378 South West Temple). I bribed the shop to help me out and it only took us about 15 minutes to put all 4 on. The cool trick is LUBE, multiple people (2) and some serious pushing. We actually put the insert on the ground, chocked it with wheel chocks, set the tire perpendicular to the insert (lots of lube) and pushed down. Worked pretty good, and I've got all four inserts in the 38" SX's.
I can't imagine having too hard of time putting the wheels together (famous last words?) but if I do, I'll report on resolution of that.
EDIT: The only problem I had with putting the wheels together was getting everything bolted together so the wheels didn't leak. Gave my impact (and compressor) a workout. There are three methods I've found during my H1 wheel tech search to 'stop' leaks, silicone, grease and a 'new' o-ring. I have new o-rings, so I thought I'd try that on one tire, grease method on another and siliconed the other two. I marked the inside of the wheel so I could tell which method worked better.