Are you hard facing with brazing and/or soldering processes?
All of it I ever did was with SMAW or FCAW, and on pretty heavy equipment for logging, earthmoving, mining, etc.
So, could you give us a little more detail? Even if you are brazing on smaller parts to hard face certain areas, off the top of my head I know of few places that train to that specific criteria. There may well be some, I just have not heard of it.
I learned by in house training at the facility I worked at with lots of questions and conversations with other welders, reading manufacturer's specs, asking questions of the welding suppliers, etc.
But, more formal training may be difficult to locate and expensive to pay for as the process's electrodes are not cheap.
Have a Great Day, Brent