Good to see you went the parasailor route
mate. For short handed downwind cruising they are hard to beat IMHO. Unfortunately we didnt get too much downwind sailing this year in Greece
(although last year in the Adriatic
it was gold) so still tweaking but for what its worth -
I agree with Rubikoop - let it out. In hindsight we had ours sheeted on too hard to start with like you would a normal spinny but they want to sail a bit higher to get the best shape due to the wing.
My lower tell tails dont do much either below around 10 to 12 knots tws. Above that you can use the luff and leach tell tails to adjust the guy/sheet as needed to get these streaming vertically. The actual luff and leach dont tend to be as easy to read as on a normal sym spin as i guess the wing gets in the way so maybe it is easier to oversheet.
We messed around with different combos of the 4 lines and for most situations the windward guy and leeward sheet worked best. For DDW we used both guys especially if there was any swell about as that seems most stable but fly it higher than you would think makes sense and check your boatspeed. Even 5 degrees off DDW though and guy / sheet combo the best.
Have found this sail pretty good in gustier conditions too. The real plus is it self tends and seems a bit less prone to collapse as the apparent wind shifts around which is especially handy on cats as they accelerate on the gusts rather than roll.
On the take down sailing as a couple we ease the guy first and have had no issues in up to low 20s TWS. If we ease the sheet too soon the wing does sometimes tend to get caught on the feed back into the sock.
Back in Oz now and jealous your trip is continuing while I have to wait till next year for the Atlantic now. If you need short notice crew you know who to call!