Dirt bikes, 100's of times. I rode every day from the time I was 9 or 10 until I was 18.
FZ6, once. 0 MPH making a U turn in my work parking lot, cut it too sharp and just fell over slowly. Just a scratched frame slider.
Flat rate on valve checking is 3.6 hrs according to my flat rate guide that I use for quoting customers. Sounds like you got taken a little bit, I can get it done in about 2 hrs if no adjustment is needed.
Remember, when you go to a UPS store or PAKMAIL they markup consumer prices sometimes as much as 100% on top of what you could get by just sending it out yourself, not including packaging.
Also, be very careful when handling the tank. The metal is very thin an can dent easily. Don't drop the orbital sander on it.
I would remove the fuel pump, just to be safe.
He is the seller I bought mine from about 4 years ago, they were a bit cheaper back then ($560?). Fit and finish is excellent, quality is excellent, sound is pretty decent. I still would buy them today, they are worth the price.
Maybe try a group buy with this forum, that is how I got a...