I've seen some setups that utilized a small fortune in fittings trying to jump from one size/style to another. Real plumbing nightmares. They work, but if you can find a reduction coupler you will be all set with a minimum of hardware.

http://www.usplastic.com/catalog/item.aspx?itemid=28690&catid=551

"Forget pounds and ounces, I'm figuring displacement!"

If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.