gain extra pulling power so I setup a sweet triple-line pull. The problem was, the winch line slipped off the pulley (most likely because we didn't have anyone watching the rigging when it got taut) and burned up 2" of my synthetic winch line (new rope on the way ).

I wasn't pleased with how the snatch blocks lined up in the first place. The D-rings can't go into the loop on the snatch block, so you are limited as to the angle of the pully wheel. One was horizontal (pinned in the cab of the stuck truck), and the other had to be mounted to my bumper, which caused it to be at an odd angle.

Actual rigging snatch blocks seem to have a swivel joint of some sort with the shackle attached:
http://ep.yimg.com/ay/yhst-88039420719426/crosby-6-417-alloy-snatch-block-w-shackle-168972-5.jpg

ATV/Jeep snatch blocks are a split design with a hole/loop (and most won't accept a 5/8" D-ring shackle). I don't want to use small/lower rated shackles to fit the hole...that doesn't make sense, so I must be doing something wrong.
http://autoplicity.com/content/images/1435/14353529_0.jpg

So my stupid question is: To align the Snatch Block pulleys properly, do you shackle short tree-limb straps between the bumper and the pulley, or is there a shackle/attachment that I'm missing here?