Hi Kevin; and welcome!
A 12" in that size box may work just fine
.....or it may not
A couple of questions:
Do you have the White Paper for the driver? Or at least the Thiele Small parameters for the thing? If you have the specs we can plug the numbers into the formulas and find out what kind of box and alignment is best.
The 0-180 question probably has to do with the phase that the driver sees.(Kinda like changing the leads going to the driver) Set it so that the speaker is loudest!!
When you say "not very loud" are you talking about just not enough volume, or is it "bottoming"; Actually "Hitting the Stops"? Having the specs will help with answering that question as well!
Just having the name and model number would help
