I ordered the copper and the endmills today. The copper should be here in a few days but not sure about the endmills. Never ordered anything from this company but they had 3 flute 1/16" endmills! I even got a 3 flute 1/16" Ball nosed endmill. Also picked up 2 3-flute 1/8" endmills for the actual milling of these blocks. They were under $5ea. to boot!
The 1/16" is for the O-ring groove on the GPU block and some other projects in the design stage.

Hopefully the endmills will get here before ThanksGiving.