Hi need some advice from those who are more knowledgeable in this

I want to install an awning but i scared get potong/given cap ayam low quality material end up leak easily. I did do some research, my target awning board is mostly ACP or PU Metal Deck. The beam and column I will most likely use stainless steel to avoid yearly repainting.

I need advice on following in terms of no leak

Acp or pu metal deck better for long lasting no leak?
The acp must be how many mm thick for high quality?
The spacing between the beam mu's rbe how short to prevent bending of the acp in future?
The joint between acp panels how to joint properly? I saw YouTube got several methods, some got a joint panel some just silicon, then aluminium tape
The screws used should be how?

For pu metal deck, I read mud have bottom side metal also to prevent the foam peel off. Other than that any comment/recommendations?

Thank you