I had the same problem with the offside at stock settings - the ski would not cast out. Removing length and moving the bindings a little back for me really helped.
I'm on a 66" with FM hardshells at 29.25" (34 mph). (run almost all 32offs, just starting to get some consistency at 35). My end of summer numbers were 6.902, 2.505 and .753, wing at 8. I've been doing some fin tweaking for the cooler water, but I think the base problem was that I was cold. Once we moved to drysuits, the skiing consistency came back.
I'm currently using the stock fin, but need to re-try my carbon fin from my older Nomad.