THey seem to be both applying the glass onto a still wet precoat AND thinning the precoat epoxy heavily with Xylene to improve penetration. I wonder if anyone has tried just the thinning part, letting it harden normally. I have no desire to apply glass over wet or sticky epoxy!

The amount of xylene added was really high as well (>60%??). I recall WEST testing that indicated anything above about 5-10% solvent would result in weakened epoxy - it becomes essentially a sponge after the solvent evaporates.
With that much wet solvent in the wood, I'd hesitate to 'seal it in' with glass and regular epoxy on both sides - it could be interesting the first time the boat sat out in hot sun conditions.