AFAIK, there's no relatively easy way to put a dual beam bulb in either socket on the 2G B6 or 12. It is fairly easy to put a high beam in the low beam lens, you just have to trim the alignment groove on the bub. It still won't be quite as bright to the oncoming traffic since there's a diffuser in the housing.
The diffuser can be removed from the lamp housing for more light, too. You'll have to remove the housing and disassemble it, which requires a heat gun or hot blow dryer and can be a little messy. To reassemble, just heat the goo back up and stick it back together.