If you have the time, the next day is perfect. I think next day is almost mandatory if you use 2 wet coats. For one coat, the minimum time is an hour or so, but I have had that come back and bite me in my cool environment. Wait as long as practical.
I bought a box of the maroon ones. They sure do work good.
The is a new hood panel and had ecoat on it. It's tuff stuff just like epoxy. The maroon pads worked well in those corners and on the braces.
I epoxied the underside yesterday and have it in the sun now. I'm going to flip it over and work on the top side and get epoxy on it today. I guess I have the choice of leaving the ecoat and just d/a to scuff or go ahead and completely remove it.
From what I've read here it's really not necessary to remove it. It would only take just a little more time to do it though with my d/a and 80 grit.