I neck size for my 357 Herrett in the Contender. The Contender should close with a bit of a "snap" to indicate you're headspacing on the shoulder and not on the case head. YMMV.
+++1! Neck sizing MAY allow the action on the contender to close "with a snap", but not close with a gentle closure.
My 7 X 30 Waters contender is set-up this way. If closed gently, it will NOT lock up. But closed with a snap, it locks up fine.
Now here's the problem. If you don't get that snap, you
WILL be having case head separation problems. If you set the shoulder back too much, you'll be stretching the case webb too much, separations will result.
My advice is to use a FL die that is backed out one full turn from contact with the shell holder. Then try the sized-but empty case in the barrel, try to close the action. It won't go, then gradually turn the die down, closer to the shell holder, then try it again. You'll find a spot shortly before the die contacts the shell holder where the action can be closed by rapidly closing the barrel to the receiver, the "snap".
The rest of the loading is pretty straight forward, the only difference is you don't have to worry about pointy bullets in the single shot. Not many 35 cal bullets are pointy, so it's a minor concern.