But how to just rough the 3 slots?

They are 2mm wide with a 3mm loop at the base, I was going to go in with the 2mm finish tool.

Is it as simple as defining a second pre-finish pass with the 2mm tool but still leaving the same allowance after?
But then that would not fit into the slot as its 2mm tool in a 2mm slot + 2 x 0.1mm allowance.

Or are we saying go down to smaller tool?