On the paint subject, I find spar Poly is not needed, you dont leave your boards out in the weather 24/7 so UV damage is zill, all polys are water proof, with the exeption of water base polys. Bottom line with any finish is at least 6 coats. With fast dry Polys you can put 7 coats easy in 2 days.
If using epoxy a protection coat of poly should be used over the epoxy for UV protection, The epoxy must be washed with soap and water very very well, then sanded lightly well, then polyed, If you dont wash the emines off the epoxy surface, the Emines will change the chemical complixes in the poly, and the poly will NEVER dry.
With a colored surface, a simple method is to have your local hardware/paint store ad a small amount of color to your fast dry poly, works great. Cost 10$ instead of 30+$ for marine polypaint, and you can have any color under the rainbow.
Plastic Coat paint works great for edges for a sacraficial layer, super shiny,use a brush, thick, drys to the touch in 30mins.