Calculate coil winding width and depth?

[Jdiffer]

Hello all. I can't find any info that helps me out. I know it's out there, I just can't find it. How do you calculate the winding width on a voice coil? Also, how do you determine the depth of said coil, like the xmax? What determines the power handling of the sub,(motor size)? I have a couple of raw motors and would like to build them up to take abuse. One was rated at 1500rms (tantric HD), but a builder told me there is no way it would do it when I gave him the slug measurements. I'd like to learn how to figure all of this stuff up so I can properly build and use these subs. Thanks!