If your Pro 901 is the same as mine, you'll want to dress the slot with something like a Bastard Mill file. If you have access to a mill, it wouldn't hurt to widen the slot by as much as you're comfy with. I use Polar Wire Arctic Ultgraflex Blue 10 and 12G wire on my trikes. http://www.polarwire.com
Turnigy is a good choice for wire but the service at Polar Wire is far superior to HK. As always YMMV.
05 Catrike Road (Yellow), 20" 48V 1000W GM hub motor,12s24Ah Lipo batt.
12 Catrike Expedition (Candy Purple), 18s32Ah Lipo batt. Lyen 18 FET low RDS controller, C'Lyte HS3540 hub motor, CA-SA, Mueller Bros. Windwrap XT fairing, Terra Cycle Cargo Monster extension. Still evolving, should be interesting by next Spring.
2011 Roll Over America tour, 50 Velomobiles, 5000 Km, 24 days, Portland, OR-Washington DC, July 28th-August 24th 2011, damn I was tired after that.