I haven't used one of those, but have a similar one that attaches to my Oster Kitchen Center, and I love it! Your grinder has much more power than mine, and the juicer has a bigger hopper, so I would think the Cabela's juicer would be even better! No peeling, coring, straining, etc., just plop them in there and it does all the work, spits the juice out one side and the garbage out the other, voila!

And the Cabela's attachment looks just like the Roma, only you get to attach it to a good stable base (your grinder) and don't have to hand crank, so I can't see where you could go wrong with the Cabela.
The only down side I see is that there don't seem to be additional screens available, but I bet the Roma or the Victorio sets would work (they work on my Oster clone).
Roma Accessory Pack:
http://www.amazon.com/Roma-Tomato-St.../dp/B000S2L0AY
Victorio Accessory Pack:
http://www.amazon.com/Victorio-Model...5938822&sr=1-1
Of course, that's assuming you'd even be interested in those screens. I use them a lot myself. Good luck, and by the way...I have grinder envy, lol!
P.S. If you do decide to go with the Roma, look around. I think you can find it cheaper than Lehman's. Amazon is cheaper, plus you get free shipping.