I just did my TT PRO 46 overnight in a crockpot with Prestone. The engine was completely disassembled, since the rear bearing needed to be replaced anyway. I soaked the Crank case, muffler, crankshaft, and head. The rest (piston, liner, carb) I left out.

Came out looking fantastic. A light brushing with a cheap toothbrush to remove the remaining goo, rinsed with warm water, dried it, wiped internals with a little 3 in 1 oil until I get to reassemble it this weekend.

Can't see any reason to use any other method anymore.

Brad