Noob with a new mx5 Saturn build.

[Bonzo]

Personally I would use a stainless countersunk screw of the correct size to suit the popper.

You could also get poppers that are a screw fit.

Another possibility is to pack the back of the popper with washers to stop the alloy deforming.

Here is one of the types of popper I use.



Ebay is a good source of all things related to cover fixings, just search for " Boat cover fasteners "