Thanks for all the good suggestions. I love that nut splitter, I think I'll order one of those.
I had my mechanic install this helm about 5 or 6 years ago, that's about all I get out of a helm on this boat, the shafts rust and they get stiff. He told me that he couldn't find a stainless nut to fit it in his shop and that I should replace it, but I never got around to it. I hate the way it looks, but honestly it didn't really shorten the life much as the shaft is as rusted as the bolt is. It's a teleflex helm, seems like they would use a stainless shaft but you know how that goes.
I'm stuck at home like everyone else, so I decided to change the helm myself. Now if I could just figure out a way to jury rig a wheel puller.