I tried to make one like the on Cabelas sales, a cup type, but it did work to well. Of course I tried it on a BB bronze turkey. I don't think the one I made spun fast enough for the type of finger I was using. Since we are finished with broilers for the year I didn't have a chance to try it on any chickens. I use the bundgy cord fingers, maybe commercial fingers would have worked better.
I've know hunters that have used the Cabelas one and they say it works great for them. They have also used the drum type and like the drum type better. They used it on Pheasants.
With cornish the feathers are larger simular to a Turkeys, so I am pretty sure the cup type that cabelas sales won't work to well. The wing feathers and tail feathers may have to be plucked any way. You might consider the drum type rather then a cup type if you plan on using it for Cornish X's or turkeys.
Tom