You might enjoy this calculator
LINK I set it up for your boat with a P of 46 and 1500 pound load. It shows the stretch for various line materials. StaSet 1/2 inch is 9 inches so that is your starting point if you really get that load. If you used 5/16 Amsteel and covered half of it with the cover you strip off your existing halyard you have a very inexpensive solution with a bit less than half the stretch. For some reason I am not showing VPC to be less stretch that SatSet which is kind of odd but that is what the numbers show given the published strength and stretch. The datasheet on StaSet says the stretch is 1% at 10% of load and the datasheet on VPC says it is 1.3% stretch at 10% of rated strength. Doesn't seem right but that is what they publish.
I got the dimensions
HERE so your actual setup might be less with a mast mounted winch or a fair amount more with a halyard led back to the cockpit.