I understand that the question is along the lines of when can you use a screw with a #1 point; when do you have to use a #2 instead of a #1, when do you have to use a #3 instead of a #2, right? Here's what the Cold-Formed Steel Engineers Association has to say in Tech Note TN-565c:
Format:
nominal screw size / maximum recommended total thickness of steel sheets
For #2 Point Style
4 / 0.080"
6 / 0.090"
8 / 0.100"
10 / 0.110"
12 / 0.140"
1/4" / 0.175"
For #3 Point Style
6 / 0.090"-0.110"
8 / 0.100"-0.140"
10 / 0.110"-0.175"
12 / 0.110"-0.210"
1/4" / 0.110"-0.210"
I don't know why the #3 point style data is given in a range, while the #2 gives a single value. Evidently #1 points are for very light connections and are not worth including in this table. Suggest you obtain TN-565c -- I belong to the association, and I can not recall if it is free or for a charge.