Ed, I do slightly the same thing spare getting the cab guys (More premidonna than what us electricians are made out to be) to do it. That wouldn't fly in the local climate unfortunately. And I am often not on site when the cabs arrive, and weary of letting them cut with the wire in the hole.
I too am a metal box guy myself. Not too fond of the plastic cut-in. Over cut a plastic one and you're done.
And Niko, although it should go without saying that the wood be protected when cutting - you're right, I should put that on there.
I'm all but too capable to cut my own, but wiegh the option against the multi-K$ of the multi-trade back-charge with the slightest slip. Thinking that if they do it, it's their problem...
Personally I like to pre-drill the holes then go for the roto-zip, or just roto-zip the whole thing. Then put a 1/4" straight router bit in it for the ears. Then some #4 wood screws for support. Otherwise I have been leaving them the actual box I am going to use - which has become accepted policy locally - then let them figure it out, thinking they are capable of doing so. As said, I unfortunately been proven wrong a few times.
