The best bet to have a Red Tux offpring is with the fluoro/neon blue tux female, you will get good red tux as well as neon blue tux.
The tux girl with plain tail will give you red tux as well but not as good as with the neon blue, the others will give you a dull red tux, anyways as what SamH says,there is no harm in trying them all.
You mentioned that you wanted big tail fin, the only one that will give good big tail in the first generation is the female with the widest tail, so choose that one whichever it is.
Depending on how bent he is, he might not be able to do the job. Is he bent down because the tail is heavy or does he have a crooked spine?