Kenors, even if that logic doesnt help....we know that theres a very high chance of nothing going wrong. Ever. That's the bottom line.
So, worst case scenario. Let's say it did. Right now, there is a complete head, on ebay, for 335.00 shipped. Anyone who could do a valve adjust could replace a head. I'll bet the head replace would not add an extra hours worth of work to the valve adjust. Sure, the used head probably needs its adjustment, too, but it would be on the bench when you did it, much easier.
Second plan would be a used ebay engine. Heavy, but easy work to swap. Figure 1200.00 for it. You would get some of that back when you sold the old engine.
With that in mind, I dont know how a person can justify a shop adjusting valves. I think you are correct. If this was an Aprilia, you would be insane not to check. That 3000 you spent would buy 2 or 3 used ninja/z1000 motors. As far as valves go, pretend its disposable.