Re: paint out nightmare = hair loss

i scond rayk on the image seq, the last thing you want is the computer to have to decode compression on top of dealing with high res

other thing i sometimes do is use the crop tool on the footage controls to crop the footage only to the area of interest (presuming you are not painting on the whole frame)
you can even animate the crop to follow the area of interest, thus minimising the res, then just press reset before you do your final render.

careful when combining this with comps though, as it cocks them up

also, you may want to set proxies for your footage, depending on what kind of paint work you are doing

finally, clone / reveal tool on high res plates is a ruthless dutchess and there's not much you can do besides make sure you only use raw footage or the current op as the reveal source (ie never use something that is being comped live), and maybe approach the paint task in sort of waves, you you can periodically render out and import, and continue painting. a pain in the ass but helps stability

good luck
alex

alex