I built my -12 using the 1 quart kit of West Systems. Had plenty left over for other small projects. Van's plans still mentions the West Systems in Section 5.
There is also a fair amount of discussion over in the "Avionics/????/Fiberglass" forum about another Epoxy System that was demonstrated at OSH this year. Apparently is better in at least once measure of performance than West.
Having said that, and since you're doing a 12is I'll get quiet and let the "is" folks weigh in.
I'm also kind of hoping the Van's folks will weigh in on this topic after some time for research and reflection.
2cents,
Dave