Not sure what DCM uses but Xacto isnt as popular over here maybe, I used Swann Morton surgical blades and handles, the handles aren't cheap for what they are, but its all nicely made and the blades arent too costly, about 1 pound for 5 i think.
I wouldnt use a blade for more than 1 shell, maybe even a couple for a shell if im doing a lot of cutting. It always scares me taking the blades off / putting them on with the swann mortons though, I'm always scared its going to ping off into my eye or slice my hand open!
I have a vivid imagination! help.