Here is a chart about classes:
https://www.natool.com/wp-content/up...atp101-102.pdf
The right one for each spot would be defined on the factory drawings, but I don't remember what I have read about how to see the drawings.
I use these, instead of standard taps & dies, but I don't know if they would harm good block tapped holes:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1