I used a 1/2 bit on the lower hinge where you have to hope for the folding hinge, i also used 1/2 for the part under the tower foot to get the wires inside the cubby.

For the tube i use a 3/8 bit.

I found it best to use the stepper bits because with the smaller tips to start they dont wander as much.

Also use plenty of blue tape, and a center punch, punch it like 3xs this will help keep your bit from walking on the tube.