What are you building on, how many
coils (single dual etc.), and what's your preferred ohm range?
Basically the AWG is the gauge of the wire... Higher gauge = thinner wire = more resistance/foot. Lower gauge = thicker wire = less resistance. For example, 12 wraps of dual coil 26g around a 14g blunt tip needle is ~.67Ω. 12 wraps of dual coil 32g around the same needle is ~ 2.3Ω.
Also, higher gauge (thinner) kanthal is a bit harder to work with IMO.
If you want single
coils in the ~2Ω range, I'd recommend 30g.
If you want single
coils in the 1.5Ω range, I'd recommend 28g.
If you want single coils in the 1Ω range, I'd recommend 26g.
If you want dual coils in the 2Ω range, I'd recommend 32g.
If you want dual coils in the 1.5Ω range, I'd recommend 30g.
If you want dual coils in the 1Ω range, I'd recommend 28g.
etc.