Can you post pics of your current CP area--preferably inside and out?
That will help with the suggestions.
My first instinct if you hadn't built anything yet would be to let you CP overhang the front, but not put a bottom on the overhanging area.
That would let you use panel clamps on the inside of the front wall of the CP box, to hold down the front of the modules.
I'm guessing your current CP has a bottom in that area, as did mine, so that's probably out as an idea, at this point.
I thought about taking my saw-all and removing that are, but rejected the idea because I like the blue light there, that lights my coin door.
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As far as what's been done already, Doc and I both used bolt through the top for ours.
Some people are set on hidden hardware methods, and have opted for other methods.
I know one person used dowels and cabinet catches, but I can't remember who.
I have a few ideas based on your drawings, but will need to see the actual cab before presenting them.
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As far as other tips go, Cat 5 run to jacks at the back of the control box seems to be the best method so far for connecting everything.
This will let you have ONE mouse hack (two if you want dual trackballs, or more than two spinners), and ONE keyboard encoder, that stay in the cab at all times.
That way you just have to plug the module into the appropriate jack and go.