Welcome to the forum,
You might get better results posting your questions in the D1 section, since that applies to all the D1 codes, not just the steel code. I do have the aluminum code, but I'm never in it, our aluminum work is generally ornamental and is not usually code required and I have my hands full with all my other steel parts to stay up top of.
Also yes you are right in that you have to qualify all your PQR's for aluminum, that's a pain in itself.
Good luck and hang in there.
Chris
It's a bit of a mystery to me why there are no pre-qualified WPS' for D1.2. I have qualified several procedures to this spec. and have it down to almost a science. I think there could be several reasons for no Pre-quals, especially the stringent cleaning requirements, effects of dilution of elements between different grades of aluminum, time-at-temperature considerations and the narrow window for voltage/amperage and resulting heat input.
As for advice; if you search this forum for "aluminum" I am sure you'll have enough to keep reading for several years! :) If you have specific questions, please don't hesitate to ask.