thx again guys...
sumptimwong: no, I didn't *completely* flatten it, but it's close.

Basically I used the 1500 until I had no more untouched "low spots" or shiny paint showing through, then I went over in the other direction with the 2000 to remove the 1500 marks. The key is to check your work often.
IF this were a factory paint job, I'd have started with 2000 and relied on a paint thickness gauge to tell me when to stop.
You COULD do it by hand with OTC products, but I wouldn't recommend it. You could also pull the transmission out of your car without a lift or the proper tools, but I wouldn't recommend that either.
I went through one piece of 1500 and one of 2000, cut to fit the dual-layer foam sanding pads I have. They're probably still usable, actually.
JakesCakes: yup, with a PC, a 4" SFX1 (yellow) pad and OHC, that's what I used on the rocker panel. Worked like magic (after about 3-4 slooow passes).
tumbler (simon?): probably a pretty significant reduction, but again it's not a factory job. I'd be extremely leary of working on a factory job like this without the proper tools - a paint thickness gauge, preferably multi-layer reading gauge... for like $3500 heh... at LEAST a basic gauge.