Don,
I used Klasskote reducer for my first efforts. We are only dealing with ounces here, because I'm just thinning the paint for spraying. Primer, white, blue, red, and clear - I used about 20 ounces for the whole plane (704 square inches). Now that I have learned just how well this stuff covers, the next big plane might take even less.
I have two gallons of Dupont 3608S lacquer thinner left over from my butyrate dope paint collection, but have not tried them yet with the epoxy. Maybe I'll try this when I refinish one of the older birds this winter. I'll let you know.
I use Ace Hardware lacquer thinner for all clean up. It's the cheaper stuff.
Ron