RE: I'm going with the whisker biscuit, but which one?
All models function the same and will shoot the same. Just make sure you get a newer style biscuit that has the black fibers at the bottom and brown elsewhere. You now have several sizes of biscuits (hole size) to choose from. Get the one that offers decent clearance for your arrows. It's not a huge issue, since you can remove the biscuit and make it slightly larger by bending it.
As for model, the Deluxe offers veritcal adjustment AND a set-screw to keep it from twisting around the mounting bolt.