one can appreciate that you'd like to be interactice with your project. As a contractor i do get much of this, so let me give you a contractors point of view.
First & foremost, the shop must be laid out as to what electrical loads are going to exist and where, then pipe/wire/breaker sizes will follow
Second, a 'commercial garage', in art 511 of the National Electrical Code dictates specific area's of hazard, which must be considered when installing any circuitry.
Third, there may be an inspector to hold the job to these standards, so it is imperative to plan it well. There has been many a job that has not passed, where doing it twice has simply compounded costs. There is also the issue of liability for you as an owner of a commercial garage serving, or employing, others.
Lastly, should you wish to participate, i would ask a contractor to do so as a helper here. You can detail you wishes, and then be the 'follower' or 'gopher' if you want. I've personally arranged many such senario's with good results.