1. Reefing line is on a padeye with a ring hitch port side of boom.
2. Reefing line runs through cringle and back down to a slot in the boom.
3. Slot and padeye at same distance from gooseneck.
4. There is an internal cheek block inside the boom which leads the reef line to an exit near the boom-mounted winch.

1. Big belly in the reefing band (see panoramic photo below).
2. Tendency for the sail to be sucked down into the slot in the boom, very bad if this happens. (Photo 4)
3. To see if moving the dead-end aft made a difference I used a snatch block on the end of the boom (Photos 5 and 6). This pulled the reef band much flatter, but as it turns out if I pull the cringle aft, the slot and pulley are a good 2" forward of the "clew" of the first reef.
4. The implication, I feel, is that I need to move the attachment point much farther aft and the cheek block at least 1" aft of the straight line distance from the luff to the leech at the reefing band.

Type: double-braid or high-tech?

Strength: at 5:1 breaking-load-to-working-load ration the following figures imply around 16,000 pound breaking load.

With the above load figures this implies a 7/16" or 1/2" high-mod line such as Validator II or Warpspeed

Am I missing something here? This seems like much stronger line than most. Perhaps the load estimates are too high.

As I think about the line loading problem I am wondering about the loadcalculations.  I calculated Main Sheet Loadings (below) when choosing winches based on the formula on the Harken website. Are these the formulas you are using?

Another approach is "how many pounds can I apply to a line with my winches"?.   Based on my arm strength and winch sizes (32 on the reefing winch, 40 on the halyard winch) the most I can reasonably crank into a line with a 10" handle is 30 pounds * 10" / 12" *  power factor.  This works out to be 25X the Winch Power Factor.   For the 32 winch that is 800 pounds and for the 40 winch that is 1000 pounds.  On the mainsheet I have a 5:1 advantage but on the reefing line I only have a 2:1 advantage with lots of friction.  So although you and Hasse have calculated a maximum load with gusts of around 3400 pounds, all I can crank in with the winch is 1600 pounds.  The load on the mainsheet might be 3400 pounds, but it's unlikely that the load on the reefing line will be so great except in gusts.  It's true that without the sail slugs the load has to be divided between the luff and the reef cringle. 

Starzinger and Evans say that reef lines should be moderate stretch (3 out of 5) and low weight (4 out of 5) 

"Reef lines tend to be shorter and lower than the halyards so are a little less sensitive to stretch and weight, but is prone to chafe from the many sharp turns and experiences a lot of flogging. They typically use line at one notch down in sophistication/cost from that used for the halyards"

Maybe there is some practical experience here that dictates reef line size and quality.  At this time my biggest problem seems to be chafe and I think a lot of that comes from the misplaced dead-end and cheek block positions.

1. Halyard restrainer at exit point
2. Tighter luff when running downwind
3. Addition of chafe cover (e.g. ICE) if room