It's easy enough to shorten the arm on a fuel sender if it's too long.
I don't think it matters too much which way the outlets point, I'd position them in the most convenient location/direction for the fuel line routing.
If you're worried about fuel slosh, it's common to weld in baffles and add a pot on the bottom to take the outlet from like Kev did on mine:
And you definitely want either barbs, or a flared end or something to stop the pipes falling off!