Thinking through the logistics of making a deco habitat, but wondering whats a good size for a 2 man habitat. My initial plan was to use an FIBC as the outer bag - because its tough/cheap/available/can withstand 1 tonne of upthrust on its built in loops (I think), and to have an inner airtight/waterproof bag. Problem is the FIBS's dimensions are 90cm x 90cm x 90cm.
That might be a little tight for 2 divers.

So now I'm thinking a little bigger may be better, perhaps 1.2 to 1.4 m3, but that necessitates having the habitat custom made. Recon the seams need to be welded to make the watertight - so was thinking pvc / butyl something like that. I heard of a material called Dura Skin - anybody used that for a habitat?
Needs to be flexible / dismantelable for practical transport reasons. Can anyone suggest a good place to have this made? Was thinking about places that supply pond liners / swimming pool liners...

Thinking of using ALI scaffolding poles for the frame as they're lighter than steel (so easier to transport in AND out of the water, and shouldn't rust, but they're quite pricy. Any ggod suppliers / alternatives?