My leather Brooks saddles don't tear up my shorts.

I put Proofhide on the edges of the leather (down on the skirts of the saddle, especially) to make them fairly soft and silky.

Maybe your An-Atomica just needs some Proofhide on the edges?

(PS- the An-Atomica's are on the pear-shaped side of things. Maybe you need a more "T"-shaped saddle to prevent the rubbing?)