Thanks for your great help. Your advise is noted.

Thanks!!!Please also advise me if the heat from the metal roof so close to the plywood ceiling does any distortion to the plywood after some time.

Ok,. I had posted another clearer picture. Hopefully that will give an ideaThanks!

Hi, Please advise me if I can use 3mm premium plywood for this job? Light weight have to bear in mind because the whole roof is supported by cross bar ...