nodachi1 wrote an answer about DMM Wallnuts Sets on June 12, 2011
I'm doing something similar to how you would do it. I've got a set of 1-11 Wallnuts racked on 3 wiregate carabiners (for small, medium and large nuts). I'm not too fussed by the carabiners themselves, and have BD Neutrinos and DMM Phantoms (v light). I like the conventional shape of these carabiners for racking, and have never considered an oval.
Basically an average wiregate is enough, so just get a cheap one from a decent brand that isn't excessively heavy.
A non-clean nose is probably quite handy for not losing nuts, but can be quite annoying when you want to get a nut off the racking biner. I don't worry too much about losing nuts off my biner to choose between clean/non-clean noses. However, I've lost a biner of nuts, because the biner itself didn't clip on cleanly to a friend's harness (carrying lots of gear)... subtle difference there.