IMHO, both tuning methods have merit, but when you are consulting with a professional on tuning, the dyno in a shop setting clearly makes the most/best use of your time and the paid professional's time. That's why Dynos exist in the first place.
At the track it's: make a pass, make a change, wait in the staging lanes, make another pass, etc....Plus, you won't really know the HP and torque curve, only your 60ft, ET, and MPH in the traps, ...and with all of influence of the driver's variance (at least in my case) pass-to-pass on top of that, to pollute the results and have you tearing hair out because you don't really know for sure if that last change you made got you quicker or slower, which is fine and dandy if being at the track is your car's purpose, or it's your hobby, or the track is convenient for you.
But for a lot (most?) of us, that just ain't the case. For me, I'll be lucky to get there 2x a year. The dyno is convenient, eliminates huge contributing measurement variables, and because it is a calibrated measurement device, is infinately more accurate and repeatable. In my case, right now, I don't want to measure my car + my ability to launch my car, I want to measure my car. ET's and associated bragging rights, if any, can come later on.
Also, for those of us who have dyno'd their engines alone, we can measure what kind of rear-wheel HP and torque we are getting once installed in the car.
For me, in San Jose, $200 for a dyno tuning session with a professional tuner, is very reasonable. The Mustang Ranch dyno fees are between 75 and 100 bones, plus you are paying a professional person $100 for his time. Add to this the consideration of how much money I have invested in my car, and for me, it represents a good value. (And, it will be fun, too, which, I think...is why I have these cars around...)
It sounds like a great opportunity to me, so count me in!