Deff buy your kanthal direct from temco(amazon or ebay, I find better prices via amazon) going that route, 25$ gets you a lot.....like 5+ years worth of kanthal. On size and ohms per foot.. really depends on twist. I can honestly say twisting wires gives me a different ohm/ inch reading every time. Is it a big difference, no. But like all things, there is a technique to drill twisting to get ohms consistant... also worth mentioning, your before firing ohm reading will rise after firing and, if you do so( contact coils) pinching will also raise ohm by a .1 or .15