(1/4 inch is recommended, 1/2 inch is hard to use in tight spaces)
Thanks for the great write-up!!
My 1/4-inch Craftsman ratchet was too large for the bottom IAC bolt. I used a mini combination wrench (8mm or 5/16-inch). You don't need alot of leverage - IAC bolts are only torqued hand-tight. I also found a telescoping mirror to be helpful.
Before starting, grab a handful of Q-tips -- you'll need them to help the cleaning fluid do its job.
This job is definitely do-able -- but requires PATIENCE!!