Thankyou, it’s currently set up with roller boom reefing pain for raising the sail as you need 4 hands half the time, the sail it’s self is set up for slab reefing. I’m currently thinking of getting the hook on the gooseneck to go into the holes in the sail my boom has the pulley and cleats for the first and second reef my problem just is the big gap at the bottom of the mast it won’t make a differnsce when reefed but if I wanted to take them out I’ll have to go to the mast to put the cars back into the track?That is quite a big gap in mast luff slot. I imagine you would not find any purpose made ali but bits of strip may be able to be pop rivetted to the sides of the mast over the area. Then fit a gate to hold the slugs in place with sail down.
Now I presume and suggest that you use a 2 line reefing system with a clew reef line and a tack reef line. All very good for one reef perhaps a bit messy for another reef. Certainly makes a better easier reef than single line system IMHO.
Problem can be that using slugs on luff when you reef the slugs on the reefed part of luff pile up and may need to be released to get tack down to boom. That may be OK but do make sure the reef tack eyelet is pulled well in to mast against outhaul with the tack reef line. (not just downwards)
One solution for one reef is to omit slugs on that part of luff. ie bottom 80cms.
I use just bolt rope in mast (no slugs) a bit more tedious when raising main sail but means easy to reef as bolt rope just pulls out. ol'will

last thing you want is to start going forward & releasing sections of the luff.Problem can be that using slugs on luff when you reef the slugs on the reefed part of luff pile up and may need to be released to get tack down to boom.