Interior Cargo Net

[Gunflint]

So I've been considering installing a stretchy cargo net to the ceiling of the van, a place to stuff simple stuff while on road trips to keep them out of the way. Books, blankets, pillows, jackets….etc.

Sounds simple enough, and I imagine it is. But here is where I need a little help. I am not sure how to go about it. I figure what I would do is screw 4 small hooks into the ceiling, one for each corner of the net. The only thing is I am nervous I am going to punch one of the screws all the way through the roof. I can imagine the sheet metal, where there is not a support, is pretty thin. I suppose the logical thing to do would be to be sure and hit a structural member. But I am not sure how to go about being sure where they are and that I won't also hit some wiring or something.

Has anyone done something like this or could they offer up suggestions?

Thanks!
Matt