Can you recommend a type of hurricane nuts?
Whatever fits.
Would you use a typical glue like Titebond II or use an epoxy?
Any typical wood glue will be fine. Hammer 'em in nice an good though.
I agree that the 15's would be much more powerful and have a better sound in general but the value in the 12's is so much better for me.
Maybe you need to get the Stentorians built before you make his leap. I honestly feel you would thank yourself for shelling out the extra money, but before that, you need to get an idea of the value behind what we've recommended thus far.
You're pinching pennies when you're this --><-- close. We're talking an extra week, maybe month, of saving up, yet contrast that with the time you'll spend actually enjoying them. The dayton will flat out play cleaner, louder, deeper, and the amp is better too, to the same extent.
Don't get me wrong, I think that the Infinity would be a fun build for the heck of it, maybe in a random living room but this is your dedicated HT room here. The real investment isn't the extra $200, it's gonna be the time spent building. Why not get it great the first time?
I've seen some posts that discuss subs and sub building and programs that help people design a box. Is there something that would take the driver and amp I'm using and give me a box design with dimensions including port dimensions?
Designing a box isn't hard.