So far I've just been chopping 2x4" feathers from wild turkey and goose, so I can't comment on purchased full length feathers.
I do manage to get 2 out of one for nearly all the turkey feathers and a little less than half the primaries from a goose wing.
Bill, I dropped the blade on my pinky finger last weekend as well!
I'm using a Little Chopper now from 3Rivers, but in the past have used one of the two choppers I made. This was the first one I put together:
The second one had a bunch of improvements, including a feather clamp made out of paperclips. The next one will have a few other features that'll make it real easy to use for left or right wing feather. They're easy to make.