Does anyone here know about the weights of canvas?

[olicana]

I'm looking to buy natural cotton canvas sheet to make a 'desert / arid' table cloth. I've found a supplier who does it in a 9 feet wide bolt in two weights: 7.5 oz and 10.5 oz. I don't know how thick that makes them. I'm guessing I should go for the heavy one but, is this too stiff / thick to lay well over hill shapes, etc.

Any advice would be appreciated. Thanks.

[Captain Blood]

No cross posting in multiple boards please. Have moved to workbench