RE: Selway Stringer for high poundage bow
It would really depend on the weakest link of the stringer. I know my stringer is made from parachute cord which I believe is rated at 200 pounds. You're not fully loading the limbs though when you are stringing or unstringingthe bow. Just be careful though, John Schulz's brother Dan lost an eye unstringing a bow.
You may want to contact Selway.