To Seal Coat of Not?
I have to say I'm a proponent of using a seal coat. I have developed a process of rolling it on with a foam roller (made for use with epoxy) that quickly lays on a nice even layer that seldom runs or drips. I then scrape off as much as possible while it is still wet (see building a light weight boat).
Whether you use a seal coat or not depends somewhat on the nature of the wood underneath. Wood with lots of curvy grain will be inconsistent in the way it soaks up its first application of resin. Wetting out cloth on dry wood may take more attention to baby sit those areas that continue to soak up resin.
A case can be made for not using a seal coat on the outside, but on the inside I see a clear advantage. I like the weave of the glass to show through to make it less slippery. But one layer of resin is not enough to make sure there will be no pinholes to leak water or water vapor at a later date. With a seal coat underneath the glass, pinholes are not likely to be a problem. The alternative is to add a fill coat to get the second layer. I think this will use more resin and weigh more than using a seal coat. Sounds like an opportunity for a controlled test.
The disadvantage of a seal coat is that there is one more resin step (at least on the outside) in the process and one more roller gets used (if you use rollers).