Don't sweat it. Glad you're having fun Ranger. That's the key.
If you were in the market for some additional input, I'd like to suggest the following:
2 players: Did I hear you say you wanted this to be for 2 players? I noticed the monitor is vertical, there isn't a lot of 2 player simultaneous vertical games, at least, there are much more 2 player horizontal games. Did you plan on 2 sets of controls and a vertical monitor? It may work out better to be configured with a larger horizontal monitor.
Nails: You may want to switch to screws for a couple reasons. You can recess your screws and cover the holes for a cleaner finish. They hold better and won't pop out when/if you move the cabinet.
Monitor: Check to make sure the monitor visibility is good from viewing it from the right and left side. Flat panels can have a poor viewing angle in vertical position.
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Front End: Definitely spend some time looking at front ends. I would suggest MALA if you are fairly new to front ends, but definitely check out Launchbox and Hyperspin. The Frontend is what folks use to selct their games and it can really make a cabinet feel more professional with no additional cost.