The furler, and the luff tensioning system.

You know the system you have is not going to be efficient with a furler. It's a very good system for a hank or wire luff sail which comes down when you're not using it. Due to the twisting force the W/M gear is going to generate no matter what you do, you will probably develop twist in the halyard. Everything about your rig, other than the W/M, is safe and simple operation. So my first and strongest suggestion would be to get rid of the W/M, take the sail down when you don't want it out there.

If you really want the furler, the next suggestion would be to place a permanent stay to the cranse. If you're leaving the sail up anyway, and the bowsprit is not rendering, there is little benefit to having the halyard/luff tensioning system while there are drawbacks such as weight and complication aloft.

If you specifically want to work with the gear and rig already in place, by all means move to braided low-stretch halyard. I would not suggest going to wire with a winch, in part because that's more cost and complication than just setting a permanent stay, and in part because it wouldn't suit the rig well while also introducing the opportunity cause yourself problems like cranking on the winch until the sail or the 'sprit gives way. If you go with braid, double check that swivel aloft cannot allow twisting. And don't spend for the hottest high-modulus ultra-low stretch rope, just a good quality; your boat cannot capitalize on the highest tech.

my $.02