I'm finally getting back to mounting a DRO on my X2 mill.
The mount of the scale to the mill body is sorted out and to connect the scale head to the X/Y moving parts, I'm going to use a thin piece of stainless as done here

I've ordered some stainless steel shim .254mm thick for this.
The question I have is what's the best method for drilling holes in thin material? I may have to make the holes on the side that attaches to the scale head, slots to allow for adjustment.
My milling/drilling so far has been on much thinner material.