This is really "Technical forum" stuff, however!...
I supplied Andy with the asymmetric and before sending it to him I ought to have compared it to my new asymmetric designed for the top down furler (TDF). I didn't; however as I understand it, the main differences in my new sail are the luff length (presumably shorter) and the fan type reinforcing at the head, tack and clew which is designed to curl easier than the standard reinforcing when furling.
With the old sail on a run, I found that goose-winging it was very effective since it was then out of the wind shadow from the main. Also easing both the tack line as well as the halyard made it behave more like a symmetric spinnaker. I kept meaning to build a pole for goosewinging, the problem being that it needs to be telescopic else it would be too long to store (I didn't want it cluttering up the mast or boom as a fly-away type would). As it was, I made do with a boat hook of the telescopic type jammed against the cabin top hand rail and, amazingly, didn't lose it over board.
With the new TDF sail I tack down wind - the wind doesn't need to be very far round on the quarter to power up the asymmetric properly and with the TDF gybing is "easy".
Having said all that, for downwind work a symmetric spinnaker would be more powerful - but more than I fancy handling when single handed!
Peter