Point No 5 for thickness steel sheet.

The self-drilling capabilities eliminate the need for pre-drilling, it’s because these types of get a fluted tip which could self-drill when installed, and this flute eliminates the need for a pilot hole.
The self-drilling screws’ drill point length is not always the same, it is varying depends on the metal sheet thickness.
Our hex washer head self-drilling ranges are points #1, #2, #3 and #5.