Well, this is Ries's recommended head for the A100-2:

https://www.badgergraphic.com/store/..._detail&p=2620

I have the A100/A250 combination, and that's fairly bodacious. I wouldn't hesitate to put an RR 12x20 on it. You could probably perch an elephant safely on the A100-2/A250-2 combo.