Making Solar Panel mounts, what thickness angle iron?

The 1 1/2" x 1 1/2" angle irons would give me a 1 1/2" gap under the panel to the roof. I don't see how I can get it down any lower. The 2"x 2" would be worse with 2" underneath unless I rip the angle iron attached to the panel down to 1 1/2" or 1 1/4" but need to leave enough space for the bolt.
Note that the 1 1/2" angle iron is not wide enough to accommodate the panel bolt that's why a 2" angle iron cut down on one side to 1 1/2" or 1 1/4" would be better.