Current code would of course demand 1 neutral per terminal.
Manufacturers instruction state 1 conductor per terminal for Grounded circuit conductors. The bonding terminal however are allowed 2 #14 or 2 #12 copper or 2#12 or 2#10 aluminum under 1 screw. 1 wire per terminal for larger bonding conductors up to the largest wire permitted for the particular bonding terminal which is often #6. Larger bonding conductors can be accommodated by adding factory approved lugs to the bonding strips or to the enclosure.
I have always followed the 1 neutral 1 screw but until about 10 years ago it was as many bonding wires as would fit as long as we twisted them all together.
