Best strategy for sheet aluminium holes and cutouts

[JAZZCNC]

Thanks for advice.. is there a general rule of thumb for what diameter cutter for pocketing a hole.. obviously a 3.5mm cutter in a 3.5mm hole would just be plunging and wouldn't be able to spiral in..
Whereas a smaller bit can spiral in better.

Or is straight down plunging not too much of a problem in 3mm thick aluminium with a single flute cutter? So a 3mm cutter in a 3.5mm hole would be fine to pocket.

Well you'd normaly use tool just little smaller than hole if spirling down. So in this case 3mm tool would work well. But if just 1 or 2 holes then using same size tool and peck drilling cycle with small peck amount is quicker.