Choosing a via for automated PCB assembly order
Holes on commercially made boards are usually plated through (unless you explicitly specify them as not plated). So there is no need to solder wires or pins through the board.

Since it's a plating process and not a pin the exact size doesn't matter too much. The sizes you are using now are perfectly fine (though if you need the space you could go considerablly smaller).

Some bargin basement PCB facilities have a list of standard drill sizes and charge extra for using other sizes but this is the exception not the rule.