Non standard roof rails

I've got some fairly useless non standard roof rails on my Octy. At the moment , all that holds them onto the roof is 8 self tapping screws through the bodywork. Is it worth trying to make them useable by somehow beefing up the attachment method or would it be better to bin them and get some Thule or similar/whatever bars? If I went for the 2nd option, how would I close the holes?

Any thoughts/suggestions gratefully received.