Two things,
#1 you may already know this but a forstner bit is *NOT* for a router, it's for a drill press (20,000 rpm vs. ~750 rpm). Sorry if I'm saying something obvious but I figured better safe than sorry.
#2 This isn't the cheapest way to do things, but whenever I need a router bit, I go get just the one I want from home depot or woodcraft. In the long run, it's more expensive than buying a set, but I always get exactly what I want, and the cost of the bits is spread out over a longer time so I don't mind the $16 once in a while.
wm