Looks like you're bringing those back from the dead. The instructions I'm using tells you to sand them with 150 grit between coats. Two coats for proper protection and a third coat if you want it to look beautiful. I'm doing a third coat on the very bottom rib near the tail wheel because it's the lowest point.

When I started my first batches of Hysol I was mixing up too much and wasting quite a bit. I've got that dialed perfectly now and get very close to full utilization.

But with the Epoxy varnish I'm still wasting about 50% it seems. When reduced it is very thin and a little goes a long ways. You can't really come back for a second coat with a given batch (my experience). The current layer is already curing and when you try to brush more on it gets clumpy and doesn't flow. Looks terrible.

Since my first batch where I let it cook for an hour I've dialed it back to 40-45 minutes with good results (humid and cold here currently). It still only gives me about 30 minutes before the varnish in the cup starts to gel slightly, at which point it stops flowing well and brush marks start showing up in your work. Then everything left in the cup is worthless.