There are M3 versions of those heat sinks. I wish I had some more. Someone here found them for me, so maybe a search would turn them up. I would definitely get a few extra of them if someone would send them over to us here in the US.
I have a nearly universal footprint. It pretty much confirms that every vendor is slightly different. The board looks like crap - plenty of nearly overlapping drill hits.
Why? I can get less than -100dB line rejection (60Hz and higher harmonics) from a properly designed snubber, careful layout .. with a CRC supply. Now, it took some care.. but. I do have PCBs for sale motmotmotmot.