We have the 175A LN alternator on a Yanmar 4JH3TE with double pulleys on the LN Alternator, and single on the 12V alternator.
All three belts are the same... Dayco cogged belts, no idlers, A section belts
Sorry not on the boat can't give you the specs, but they're probably on file on the site somewhere 
I'll check tomorrow
Cheers
Alan
Elyse SM437