If you can find the ones that used the carbide inserts, that's the way to go. Cutters by the lb, I've never seen that. Gang Milling required such speecialized cutting wheels because every dimension was being cut at one. The widest I ever cut was a gang mill with 8 different cutting wheels. That set up on that took a very long time. Sikorsky actually put that arbor away as a single tool, as it was used often, and you could just change the inserts when dull.