I think that's a good starting point. It's similar to how I try to start out before going on the track. But remember that the engine will behave differently on the track when it's under load.
It's better to start on the richer side than on the leaner side. On the track pay attention to the smoke out of the pipe, it's a good indicator of mixture throughout the rev range. If you don't see smoke, it's too lean.
A few tips I have learned that some people might not agree with. I'm not an expert tuner yet so these are just my thoughts: when you're tuning, don't be afraid to turn the needles in 1/4 turn increments to find a baseline. This will help you find sort of bounderies for too lean to too rich. But you have the be carefull doing this that you don't get too lean. Then make smaller increments to optimize the mixture.
When you go out for warm up to tune the engine on the track, run for at least 2minutes before you start leaning. The engine needs a little time to start 'storing' the heat. I've seen people tune after 2 or 3 laps and hit 300F during the race because they leaned too much without enough time building heat. This should give you a better idea what will happen during a race. Also, be aware that the engine will lean out a little as the tank is almost empty so be aware of the resulting temp increase at the end of the run.