I think that sometimes we believe tuners have some special magic powers they are able to wield at will.
I believe that most people who have some basic knowledge of engineering tools, and especially someone like yourself with access to advanced tooling is able to make a pretty good job of tuning a springer.
It is important you understand the rationale of what you are doing, and what you hope to achieve, at the end of the day there is no magic involved.
I have used guns tuned by Venom and Sandwell field sports, either result could be achieved at home. I would add that some "professional" tunes leave a lot to be desired, at least if you do it yourself you know exactly whats been done.