Single or double?

Lots of good advice here. As far as as working on a new to you car and working out the bugs. Scrap the ac idea for now. We got all the factory ac stuff for ours and we said f that, we wanted to have less stuff in the way.
When u mock up the alt, you don't need the spacer INITIALLY that Mattax showed in his 1st pic. Once you have it mocked and in proper spot, measure the gap and verify correct spacer. Also there are different alternator adjustment arms with different bends etc.
Good luck.