No I have never seen one. However I know what you are talking about.
I sit on the Board of Directors for a non-profit organization. It has a paid Exec.Director and several employees. And also I have been in this HVAC business for 40 years.
The employee evaluation is a very important and formal procedure in the non-profit organization. It is not like this for any HVAC company that I have been involved with.
Since this is your first time posting I am guessing that you are employed by some large corporation and you are involved with evaluating employees in general. Also you have one or two HVAC technicians that also work for this corporation. Is this correct?
If so the only I advice I can give you is that these guys are probably not used to being formally evaluated.
I think in a Contracting business the employees are on the firing line all the time. If someone is not toeing the mark it is evident very quickly. Any performance problems are dealt with more quickly and less formally.