Thanks - worked perfectly first time!
When I first saw the version without a diode, it seemed a bit odd that you could tie two tx pins together (the one from the cable, and the combined one on the controller) - unless they're designed to be used this way (which the cable very likely isn't, since it has separate rx and tx lines), they tend to fight each other, and not work. Having a diode makes much more sense.
Some details, if it helps confirm what does/doesn't work:
Cable:
http://www.ebay.com/itm/121153158397Diode: 1N4148, just because I have a pile of them.
Plug: Random XLR from my parts stash
Driver: Latest from prolific's website for XP, 2.1.44.226
Controller: 50A VSI.
Software:
http://filebin.ca/qeVD8PXcQ5p/oem_programmer.zipTotal assembly time around ten minutes, most of which was finding parts.
There's still some lag, but it's much, much better. I need to try playing with the compensation and some of the other settings. The biggest problem is it takes too much stick movement to make a slight steering correction start, and seems to decelerate both motors, not just the one it should be slowing down to effect the turn. Some logic to prevent you from getting sideways, I think.
Thanks again,
--Bushytails