11mm is almost exactly 7/16 inch.
I drill a pilot hole the size of the 'barrel' of the screw. -I always use a combination drill bit for sinking screwheads. The first part of the bit is the diameter of the 'barrel' of the screw and the step, one inch higher is the size of that screw's head. (The barrel is the diameter inside threads) -I have a set of these drill bits for #6, #8, and #10 screws and they are great.
A 3/16 drill bit.
I would use a 5/8 drill bit which is almost exactly 16mm.
I use a 3/16 drill bit for that.
You use a 0.875 bit or a 7/8 bit . They are the same size.
4.5 mm is close enough to 3/16 to use that if you don't have a 4.5 drill bit
If no drill bit this size available, can use EDM service if metal is used
Use 7/64 as tap drill and 9/64 as clearance drill
Your meaning is not clear. - If you are going to tap the threads in, use a 7/32 drill bit. If you want a hole that this bolt will slip through, use a 9/32 drill bit.
Use a 1/4 inch bit, that's only very slightly bigger, less than 0.025 of a mm. larger.
If they are self tapping screws, the drill bit is as thick as the solid barrel of the screw. If you want the screw to go through easily to have a nut on the other side, then the drill bit is slightly larger than thread size.
I use 1/4 drill bit for a 5/16 lag screw in most materials.