Canvas ute tent weight 8oz vs 12oz : camping

I’m getting a polycotton canvas cover made up to go over a frame on my ute to camp in. Local canvas sewing place have said they can use Supaproof 8oz or 12oz.

Price for either is pretty similar. Weight is not an issue because it’ll stay up all the time on the ute (incl while driving).

They seem to suggest both are “the same” but I’m wondering if I should go for the heaver option for a bit more durability? Or lighter option to be a bit easier to work with? Any suggestions?