Thanks for the write up, sounds like you have done this before.
Spraying the gelcoat is way easier than brushing it. The gelcoat is red, because this is what we had. You want it a different color than the part (typically white), so that you can see when you have enough gelcoat when making the mold, and also when you are making the part.
We finished one half of the mold completely before starting the second. After popping the 1st half, and removing the cardboard barrier, I then wet sanded the 1st half. We will then reattach the 1st half to the fender (after lots of wax), and then lay up the 2nd half of the mold. When that is complete, you 1/4-20 bolt holes in the mating flange ever 6 inches. This will insure that the two mold halves will mate properly when making fenders.
We are using steel conduit for making stands for the molds. Some stands we will make from wood (the smaller parts).
You can probably do the first gelcoat layer with 3 people. We had 5, and stood around a lot when the gelcaot when going on, and curing.