Without seeing a picture of the installation on the PO's boat, which he hasn't provided, I don't think anybody can offer advice about how to prevent his problem. There is a way to install this kind of furler roll up sails properly, but he hasn't given us enough data yet.
I've never seen anybody install a halyard restrainer in the kind of application the PO has described. And I've seen hundreds of installations like the PO's and made a lot of sails for use on similar furlers.
Similar furlers are Furlex 20S, 30S and 40S, but the installation doesn't work in all geometries.
Harken 400 series for small boats are similar, but the wire in the luff is meant to replace the forestay, not be used in addition to it.
It's not at all clear to me that a halyard restrainer will solve the problem. In fact, I suspect it may cause other problems.
Judy