dude you have the same problem i do, you have a honda
i used to rebuild alternators when i was in collage for a local shop.
i went in a few months ago and asked the owner who is 3rd generation in that field.
and he told me he couldn't do much with a stock honda alternator.
he reccomended ohio generators.
and gave me the run down
these have an internal fan, and are small in size so when boosted up
they retain alot of heat which will kill them 60% faster than stock.
also when you boost up you should get a smaller pully for the alt. so it's spins faster and that will help with idel.