One thing I forgot to consider before choosing a driver to canibalise for this little experiment was whether I want the voice coil underhung or overhung in the magnetic gap.
This is a very important strategic decision.
Overhung has become the most common setup, because it provides the flattest response and minimum distortion, at the expense of efficiency.
Underhung is more efficient, has a higher Qts, but suffers distortion at high cone excursion and requires equalization.
Traditional loudspeaker designers have vigorously rejected underhung setups for woofers, because optimizing them requires electronic means; most do not like it because it puts them out of the final performance control.
A good example is the ill-fated 18Sound 18iD and 21iD, where the conflicting convictions of the speaker manufacturer and the amp manufacturer resulted in a half-assed product.
I don't know which way you wanna go, but you must establish your goal and your methodology from the beginning.
And remember, whatever you do, it will be very difficult to top 2 Tesla (20 000 Gauss).