Which table should be used to add fuel for this application?

I was just thinking that in launch control your car would be at a part of your regular fuel table that probably hasn't been tuned that much as you would never really hit that point in regular driving conditions.

Will this work for flat shifting too?

There's no reason it shouldn't. If you kept the launch control engaged, had the gas pedal down, and then put in the clutch, it would just start going into misfire again and make boost.