Drylock Aluminum Decking

u812

I was wondering if anyone here has had any experiance installing Drylock Aluminum Decking over wood framing.
Note: I'm not allowed to post any links yet because I'm new to the site so please google
"Drylock aluminum decking"
I have a customer that wants to replace all her 5/4 deck boards with this product. I don't think I will be able to use her existing framing as the aluminum deck boards have to drain away from the exterior wall and run perpendicular to the framing.
I watched the install video and it looks like a slam dunk, but I'm concerned that the aluminum boards will be difficult to lock together once you screw the boards down to match the natural variations in elevation form deflection and crowns in the joists.
Anyone willing to share their experience appreciated.

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