Full depth trocoidal milling is probably best with a 3mm ripper, drill for the entry and stepping over .3mm on the passes. Then finish the last .1 with a single pass.
I'd use a 3mm ripper from WNT (I have no financial interest in the company), the 2 flute 50 960 030 would give you plenty of chip evacuation whilst still keeping up a decent feed and has about 12mm of cutting lenght.
I don't know your spindle limitations so I can't call the speeds and feeds. Just watch the corners, obviously one wrong move and snap but if you have a cad/cam system and if it is for a possible new product you can prove it with a 1mm DOC. A bit of planning would save you lots of time down the line.
Best of luck with it.
Noel.