Dave, going to the appropriate forum section and then clicking the "Views" tab is a good way to pop up the popular threads on most topics. Reading the first 10 or so threads is often a good primer, with specialty questions being a little further down the list.
Here, I copied the resulting URL from the fiberglass forum:
Buy and use scales for ratio. They work for all resins, and for proseal. Condiment squirt containers and/or old pancake syrup bottles make good resin and hardener dispensers. Pumps suck...literally.
The world is full of claims for better mousetraps, but glass micro, flox, and cabosil are all the additives you'll ever need.
As Steve said, there are better epoxies, better mostly being a matter of structural properties. That said, there isn't much structural glass in an RV kit, so West has been popular here. The most important detail for reliable curing of any epoxy is climate control...low humidity, 75F.
If you use West, buy only a little can of fast hardener. You won't use much.
7761 is an 8-harness (look it up). 7725 is a 4-harness. 7500 is a plain over/under. At the shop level, the difference is how easily each conforms with curvature, which is roughly inverse to speed of wet-out. All are in the 9oz range. Experiment.
Learn to do wet-outs between 4-mil clear plastic sheets. It's called vapor barrier at the big box store.
Do not thin epoxy with solvents. Yes, it's common practice, but properties go downhill fast.