dual sr124dvc sealed box help

Here's my thought about it.

Talking from my gut feeling (mechanicly thinking) I would make one box, with a separator between the two chambers.
But talking from my experience, putting 2 subs in one space gives a tighter (much better) result.

It is hard to make a good choice between the designs.
But here's what I did once:
I made a design so I didn't have to choose. It was a box that could be modified from a 2 chamber to one chamber enclosure.

I made a separator (3/4" mdf; simmalar sized as the side panels), with a square openening in it. Then I made a cover/lid that is about 1 inch larger on all sides then the openning in the separator. But I also made it that small, so it would fit through the sub cut-out.
I drilled some holes through the separator and cover so I could make a thight seal with nuts and bolts. Ofcourse with a sort of non sticky sealant between them.

This simple trick gives you the opportunity to find out which design gives you a better result.

If you end up using the 'one big chamber' setup, there is always a good brace in your box, which makes the enclosure a bit more sturdy. So that covers also a part of your question.

I think a made, and designed, about 30 enclosures through the years.
So maybe I can give you a tip or two, if you encounter difficulties.

Hope this helps.

You dont need anything separating the two subs so long as youve got enough airspace inside.

This is a great website for designing your box. About halfway down you can put in all your dimensions and the shape youre wanting and itll even tell you the size of the pieces you need to cut out. Ive used it a ton.