: So, when should I apply the secong layer of 'glass and start epoxying it?
: While the first layer is tacky or touch dry, but not fully cured? Or go
: all fill coats, dry, sand smooth and then apply second layer and glass it
: as before?

: And do I need to do multiple fill coats in the first layer to ensure it's
: smooth and transparend, or do I just do one or two fill coats?

Just wait until it is not so tacky that the second layer gets stuck - you need to be able to easily move it around if you have to to get any bubbles out. No need to fill the first layer, just make sure it is clear as you put it on. I've also had good luck putting a thin layer of epoxy on and letting it set up before the first layer of glass. I also use a squeegee for most all of it including the first thin coat. Its a bit more work but the last one ended up under 45# even with four layers of 5.7oz glass (2 inside and 2 out).

Bob