short or long bed to tow 29' Arctic Fox 27 5L?

You probably can use the short bed. I've never towed a Northwoods with one (that was with a MeToo 20+ years ago).
But the angled nose would help
I doubt you could hit the cab on any turn going forward.
The trick will be backing, you may have to back-and-fill more often with short bed then a long bed.

Of course there is a solution, A Pullrite SuperGlide.

I actually have one on my 8ft bed (a previous owner) and I can jack-knife to some amazing angles