Hey, Chris - I think I have hit on a good combo, right off the bat! I didn't have a 7.2v 400 set up in a 4.09:1 box, but I did have a 6v 400 [ It hadn't been turned over in two years so it was pretty gummed up and its performance would surely have been better if I'd cleaned and greased the gearbox!]:

Tried it on 3s TP 2100 Lipolys with a GWS HD 10x6:

7.3A*, 10.8v, 82W, 5700 rpm, 410g (14.4oz) static thrust, 5.0g/W

Now surely THAT would work in an 18oz foam Edge 340 and that current draw is well within the motor's limits. I don't have any KAN's charged up, but I'll try some later.

Cheers, Phil