For the sandpaper question, I personally like to have the following on hand. Which one I use depends on how much filler I've used. Lots of filler, I start with a heavier grade paper. If I just used a small, thin bit of filler, I start with a lighter grade.
I will use the Evercoat to fill the big stuff. Then sand it down with 80 grit through maybe 220. Quick coat of primer to see how the repair looks. At this stage, I switch to the glazing putty. Sand with 180 or 220 and then primer again. If it looks good, I do a wet sand before final paint. This is a general guide.
In the shop I like to have on hand the following grades:
60 grit - very course to take down 'way too much' filler
80 grit - course but not quite a chisel effect
120 grit - Not quite feathering stage but levels the filler out
180 grit - Blending the filler to the original surface
220 grit - Getting it almost ready for primer
280 grit - final feathering before wet sanding
300 and lighter grit for wet sanding before final paint job.
Ted.
