Quick and dirty bellows?

I'm drawing up plans for a panoramic, glass plate camera based on an old Intrepid 4x5 vIII base board I have (I upgraded to the version IV base). It will use a 240mm process lens and take 240mm x 80mm glass plates.

I'm not 100% sure the idea will "pan out" (excuse the pun) so I don't want to commit to building decent bellows till I've tried it out.

Can anyone recommend the best way of making some temporary bellows? Little more that a bag bellows. What do other people do? What material and joining?

Big black contractor trash bag. Two layers may be necessary.

Black cardboard bellows and black fabric tape?

Nested cardboard boxes that slide inside each other tightly, spray painted black with a strip of velvet around the inside of the seam where they meet. You'd have to measure the distance you want them to travel and cut them to size.

You could even flock the interior with cheap black felt from a craft store; that self adhesive type for kits craft projects will do I think.

If you use 3 boxes with overlapping seams, 2 on the camera body, one on the lens board, it should make a good light trap.

Smallest interior opening on camera back, next larger one on lens board and finally the largest around the other two on the camera body, slightly extending beyond the seam of the middle box mounted on the lens board.

I have an old ROC Premier "detective" camera that uses the nesting-boxes system. It works!

I used this method (black posterboard and gaffer's tape) to make a temporary bellows for an Omega enlarger: https://www.instructables.com/bellows-for-large-format-camera/

Thanks for all the replies. I was thinking of going with a sliding box design right from the start but I want some movement in the front standard so need bellows of some kind. If this is a pano camera I need to raise or drop the lens or the horizon will always be in the centre of the image.

Simplified cardboard ones may be the way to go. I see now they can be done more simply.

I found a Century 8x10 at the flea market for $5. I made a cheap and dirty bellows by creating all the ribs from a single piece of polycarbonate. I glued the 'rib assembly' to the inside of the fabric then cut the ends of the ribs apart. To make the cuts easier, once it was all glued down, I used a punch to mark the end of each rib. This got them all aligned in one step.
I made the mannequin using foamcore board and a glue gun.