Hi I need to fix these to the wall now, they are 4m long and obviously not perfectly straight. I am wondering on the best way of fixing as the middle of the length has about a 10mm gap to the worktop. I think a grab adhesive would put too much stress on the skim on the wall so presuming screwing would be a better fix. Is this a decent method? and if it is would you cover the screw heads with a paste from the sawdust?