Just an update here. I recently picked up an EVO-S. Initially I used the stock fin at stock settings while I transitioned from my ARC-S w/CGC. After a few good sets I transferred my CG Classic from the ARC-S over to the EVO-S, stock fin settings exactly. Offside turn still awesome (was previously awesome, did not want to mess it up) Onside turn 10x better. This fin really plays well now with 2 skis in a row, totally worthwhile investment.
If I'm going to be swimming anywhere in the course it'll be on an onside ball these days (weaker offside pull, flat transition, controlled fall turn saved purely by it being onside, working on it, yadda yadda) and the difference of forgiveness onside is profound. Otherwise the behavior of the ski (which is already sweet) is unaltered.