Wish to fit on temporary basis lightweight alloy roof rack

Has any one drilled through the roof bar to fit bolts through ?

What is the material / suitable to drill through or not ?

Proper fittings that clamp on might make it sit to high hence bolt fitting option ?

Appreciated

As far as I'm aware the rails are only plastic so might not be designed to be drilled though, I think they'd loose the strength or possibly collapse ?

thanks

will look into fittings to adapt that clamp to rail standard issue

^ best way, need decent proper looking job or you could get hassle from insurers in an accident some how related to it or mentioned on accident vehicle report .

looking at sourcing just the fitting kit as got the roof bars attached to the rack