So, having no idea what I was doing but willing to learn I tried playing with the screw with a sawed-off screwdriver (I've learned not to do that again, zip-ty is now ordered). So the screwdriver slipped, missed the slot and every other thing that can mess up your turn-count, and now I'm at a best-guess setting. Until now I had never had to use the hot-start to get it going after a stall/crash and now I do - would this mean that I'm closer to the mark? Was I a little lean before? The bad news is that now even a small quick blip of the throttle will kill the engine with it in neutral. It's not affecting my riding, but maybe I'm still not that agressive from a standstill. I'll be able to experiment properly when the screw comes, but given these 2 symptoms (now needing the hot-start to start hot, but dying on a blip) I can't really decide if I've improved anything ...any opinion would help me begin to understand carburetors - I don't want to be scared to touch these things.