Kudos to the Moose! Great write-up and pics!!!
I went with the OME 2" heavy kit (towing and trail armor) and installed as soon as I purchased the truck. I installed the drive-line spacer (4-door 6' bed) and the diff drop for good measure and haven't encountered any drive line issues after 15k on the lift.
Maybe I should have made some measurements before and after but I gambled that OME did their homework. Your attention to detail should be commended BTW.
The only downside to the kit is that the truck was dead level before I put on the All-Pro
bumper and skid plate and now the front has settled down a bit. I got the heavy kit to avoid sag. Maybe I'll cheap out on a 1/2 spacer? Dunno yet. Throwing a lot more $$$ at the suspension isn't an option right now.
EDIT: Have been informed by many gurus that OME upgraded/fixed their front springs, so the old 885 or 886 have become 885X and 886X, which can be found on a dainty little tag when you get the spring. The "X" series isn't prone to sag. Dunno if there are any of the older version still being sold or if there are still some floating around in warehouses.
Follow up: Verified mine were the newer 886X. No kidding, they still sag like a mutherf@c(er.
So, in went the 13mm spacer. I did recover 1" of lift, and the overall rake on the truck is 1/2".