Sorry to read your experience was bad. I have been going there for 20 years now and have always had a good experience. A good experience for me is honesty in what they think is wrong and then doing a good job. The final tab is really not the issue for me, even when it hurts --- sort of like a big bar tab --- it must have been a fun night.
Like with everthing else in life, developing a relationship with a good mechanic takes finding the right mechanic for you plus some time, and what's good for me might not be good for anyone else. I hope you find a mechanic that you are comfortable with.
Even though your experience was way bad, I need to mention that Mostly Toyotas has also been very generous with the Club, saving cruiser parts for us to recycle, even giving us an electronic engine analyzer that was worth some serious change. Heather' carb, Jp's (I mean Mary Elen's) OME springs, Marshall's front bumper all were Mostly Toyotas recycles. Also, we got about 40 pounds of metric OEM bolts from them.
If you are having Carb issues, one of the best solutions is to send it off to Jim C. for a rebuild. That is a real specialty and I don't want anyone but an expert like Jim C. touching a Carb. I have a 2F Aisin carb that you might be able to send to Jim C. as a "core" if you can get him to send you a freshly rebuilt one. Just give me your old one once the new one comes in, that way you won't have much - - if any - -down time.
Good luck!