Here is how I have done it in the past.
I used to make these - but lost my affordable machinist and getting new ones made became very expensive.
There is a drawing included in this link if you want to make your own adapter.
I have the parts to make one more complete headlight kit......if you are interested, it is winter and I can probably find the time to complete one more kit that includes the headlight bucket and adapter.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1495732822