I'm looking forward to seeing John's outcome, especially on a 1m x-carve. When I ran into this stress test and just had to try it out. It definitely pushes the limits of the spindle. My first two tries came out like Johns, where traces are barely remaining after milling. Three things helped.
1) Trying to reduce the runout below to 1.5 mil or below. If the runout is too high, it simply will not work, since you won't be able to get the bit in the narrowest places.
2) Add the runout to the tool diameter when making the gcode. This avoids making wires and pads extra thin. the pads in the stress test should be 0.30mm. Before adding the runout to the tool diameter the pads were very narrow (0.18mm) and looked like they might peel off easily. After adding the runout they were 0.29mm.
3) Using a new bit, so the cutting was cleaner.
I'm using the same workflow I posted about before: Eagle --> pcb2gcode plugin -->Chilipeppr (with autoleveling), 6 in/min speed. Upgraded SO2.
The resistors along the top and in the bottom left are definitely 0402. They are TINY