Hi Pete,
I have used the roller reefing a bit , my problem was my spring seems to not hold well and wanted to pop out , so check that . It would be inconvenient if it happened in a blow. Also I experimented with foam strip( concreters expansion strips ) double sided taped on thelast few feet of the main sheet end of the boom to help bulk the sail out on that end during roller reefing. It does give better sail shape.
I have also used slab reefing but as I am basically a fair weather sailor and rarely far from shelter on lake Mac I don't have much of preference based on experience. Other than roller reefing is quick and simple. I never worried about the vang during reefing but I am a bit slack when it comes to sail trim as I'm never in a hurry

. Boom rolling seems to be regarded as old hat these days but I read that north sea fishing (sail) boats used and perfected it years ago . Given the horrific conditions such vessels worked in for a living it must have had something going for it
Edit just looked at dr peters pics . Your roller reefing pics Peter show your sail nice and neat with the boom still parallel to the cabin top. My sails when rolled droop the boom quite badly by this much sail rolled in which is why I used the foam. What's your secret
