Wow, that's a lot of discussion to keep up with.
1. I fiddled with block placement when I first got the sail. I finally installed them at the same geometry as the boat the sail came from, a JY 15. The angle aft is such that the line through the clew would intersect the forestay about 60% of the way above the tack. I may put them on a track for next year. Tack is fastened at the normal location. The sail clears the cabin with no adjustment. The main problem with block placement is that the JY15 is a narrow boat, and it's hard to get the sheets outboard on a run. The local Hyde Sails loft (Sailmaker's Art) suggests: run the barber haulers through the fixed blocks and pull them tight. On a run, release them and the sheets will pop out to let the sail fill.
2. The sail can be close hauled so that the tell tales (two sets) are parallel windward/leeward and upper/lower. The fabric is creaseless. All the tactile and visual cues say that the set is optimal. Only the compass reading spoils the parade.
3. The sail is probably too big to be a real "storm" jib. It almost overlaps. Over-trimmed, it can backwind the main.
4. My intended wind speed for the small jib and double-reef main was 18 knots (~21 mph). I have sailed it in those conditions a couple of times since my last post, and tack angle was about the same. (The test I reported was in moderate winds only because that's what happened to be blowing on the day my wind meter arrived and I had to, I mean had to, run out to the lake to try it.)
5. I had not thought of cutter rigging. It's an intriguing idea, but I will probably will do no more serious tweaking this season.
6. The sail drawing are great. Could I share them with my sail maker guy? Maybe we'll even get a production storm jib someday.
Which guy, by the way, says that the adopted sail probably does not fill the triangle properly and will never point as high as a sail designed with the specifics of the DS in mind. Of course, he wants to sell his own sails. So while I was there, I told the sail maker about the Doyle UPS craze. He said he would mention it to Hyde. He said that "code-zero" foresails came and went and are back in vogue again, and that Hyde is looking for new products.
Finally, I have to say that, aerodynamic inefficiencies and all, the small jib and reefing main are a total kick in the butt. My wife and I can sail the boat comfortably in conditions that used to scare us. The helm is balanced, and we can keep the clinometer to about 20 degrees. We normally put our foul weather gear away after April, because it gets too warm and we wouldn't sail the boat in conditions where we'd need it. Now I see some spray in our future, and we'll probably keep our bibs on the boat.