: Is it considered poor form to do some sanding, then add a skim coat of epoxy
: and sand again?

Mathew,
Thats exactly what you should do> Eating into the fibers weakens the weave and will eventully show as stress spots leaving you to sand off that area and refiberglass. Take the time to do each step right when you get to it, it saves time in the end.
God luck, lets see some pics sometime
Cheers
Rick