I havent used them myself, but know someone who has used 3A sigs with Atma-sphere MA-1's. He also has the 2wq sub, so while I have never heard him complain of a shortfall of bass, I don't want to mislead. Frankly, I wouldn't expect too much of a problem with the bass even without a sub with the MA1's.
I also know someone using the 5's with atma-sphere m60's, again no complaint about the bass, but the 5's have a sub too. I think the bottom line is, which OTL are you considering? Some would work fine, others might not.