That is 9mm throughout. But you would be able to get away with 6mm for the baffles to lighten it up a bit. Not sure, but I would estimate that it weighs about 100 lbs.

It's to bad you where not closer to Calgary, I got all the pieces of acrylic cut and the weld-on for $220 at Sabic. 46"L x 22"W x 18"D, 6 cambers with 2 triple baffle bubble traps plus I got the remainder of the second sheet of acrylic they had to cut into for my pieces.

I like the fact that it is light but it is a bit more work to put together then glass.