also, if you decide you want the tone of a 500k pot, just roll the tone knob down, or even the volume knob a little bit - and this will give you the EXACT sounds of a 500k - for a more permanent solution, without having to change pots or anything, simply solder a 500k resistor on the volume pot between the middle lug and the ground lug(the one soldered to the top of the pot), and this will actually make you're 1M pot a 500k pot - it's cheaper, and easily undoable. If you want a 500k tone pot, do the same resistor mod to that pot.
also, you said that the volume knob kills tone - i agree, (Note that when you turn it down very slightly, this is what a 500k pot would sound like, because the resistance is lowered from 1M to 500k) but this is easily fixed with a treble bleed mod - solder a .001 cap on the volume pot between the middle lug and the non-grounded lug.
Bit of a ramble, but i hope it helped
