Why is he using 1.0mm steel, depending on what method and material used then the articles say 18swg (waste from the rims)which equates to 1.2mm or if rolling from angle then 1/16″ (stock thickness) which would be 1.5mm. May still be a problem though.
You could always overdrill the CSK hole, the spokes will still be held radially you the csk faces of teh screw & hole, easier than trying to file or turn flush.
Looking at the photos of Adams wheels on the site he has got his screws in OK but looking at them they are probably metric and I think his spokes are over thick.
Jason