i restored my 17" alloys over xmas, they came up really good,
basically what did was this
1)had the tyres removed (which isnt necessary you can tape them up) & do the restore with your rubber still on the rim & in fact i would recommend doing this because you will save yourself about $80 in getting the rubber removed and refitted (thats $20 a wheel $10 to remove & $10 to refit) - i removed the rubber off the 2 front ones and did the 2 back ones with the rubber on, much of a muchness really. but easier with the rubber off but not much
2) i got some 400,800,1200,1500,2000 wet and dry, probably 2 sheets of each
3) use the course stuff to smooth down any really rough areas & get the surface nice and even, then tidy it up with the finer stuff,
4) when you have sanded out all of the scratches etc, wash down with clean water and dry your wheels
5) time to under coat with an etch primer ($15 a can, for 4 wheels probably need 2 cans)
6) when your primer has dried, sand it back with your 1200 or 1500 wet & dry until its a nice smooth finish
7)wash your wheels down & dry off to ensure a nice clean surface your now ready to paint
i used VHT wheel paint (silver) but you can use any acrylic paint if you want a different colour.
but i would estimate 3 cans (3 coats each wheel)for 4 wheels
all it it took me just over 2 days and cost me ~$100 and the wheels look as good as new
if you get any runs when painting, use your 2000 wet and dry to sand back the run (when dry) and go again,
well worth it imo, my wheels were in reallly poor condition & they came up looking really good