I use the hooks on the gooseneck for the tacks and the single lines run back to the cockpit for the clews for the two reef points. I can normally judge just how much halyard slack I need to secure the tack cringles without them slipping off before I get back to the cockpit and tighten the halyard; but, a better way would be to simply mark the halyard at the precise point on the clutch. I think the less time spent at the mast, the better, so I would run the lines aft. I don't find line clutter for 2 reefing lines to be an issue.
Tally ho, single-line reefing may create too much friction in the system with all the extra blocks that are necessary, I think. It's worth a try, but don't be surprised if you are not satisfied.
BTW, how many perform slab reefing while on a broad reach or run? Last day out, I was in a situation where I might have tried it, but was not certain I could bring the main down and single handing, I didn't want to spend too much time wrestling with it. So I turned upwind to luff the main. I was concerned about a broach, but found that a quick, smooth turn upwind negated any problem. I still wonder ... what if I let conditions get a little too much out of control? As it was, I had a bail out option if I had to seek shelter from the wind on the lee side of a point of land.