I have noticed most manufacturers did a tapered cut around the bulb socket for flash lamps instead of just a straight through hole for the socket on a standard bulb.

Excellent!

If you are at all not sure of working with 110V "mains" electricity in your game please get someone knowledgeable to help out. Basically you look at the transformer, electrical schematic, and or the reference card by the transformer (if there is one) - and look for a "low line" or "hi tap". The incoming 110V wire usually gets moved from normal to high tap. But exactly how this is done can very wildly from machine to machine. If you get it wrong you can destroy your transformer.