Building a greenhouse using 1" aluminum tubing for frame and 6mil plastic for cover. Trying to determine best way to connect plastic cover to frame.
Thinking about using a grommet tool to install grommets in plastic and zip ties to secure to frame,
Will 6mil plastic hold grommets or will they simply rip out? Would doubling the edge over so installing grommets thru 2 layers make a difference?

I think you are gonna be disappointed in 6 mil plastic

You need to get 4x8 sheets of plexi I did a job at northpoint with a form of plexi of course it was a higher dollar amount than your wanting to use but it needs to be able to withstand the sun

6 mil plastic in 2 summers will be destroyed

6 mil plastic will last 4 years. I have some that were put on in 2020 and the light reflectivity is still good and I won't replace until summer of 24. Polycarbonate would last a long time if you don't want to have to replace.
Grommets will not hold you need wiggle wire track and wiggle wire to connect to the frame.