Drill bit size/ NPT question

I need to drill a hole and thread it to put a fan activation switch in, I bought the 3/8 NPT pipe tap and was wondering what size of drill bit to use , Anyone know ?

This says 9/16 for 3/8-18 NPT

NPT Tap Drill Sizes - Engineer's Handbook

This says 37/64 (virtually the same I guess)

Tap and Drill Chart from Korit Sales

I got a book that says 5/16 to a R (.3390) bit depending on pitch but its not NPT threads.

The Machinery Handbook says 9/16-19/32 depending on what brand tap.

Ideally the hole should be reamed before tapping with a reamer having a taper of 3/4" per foot.

Thanks fellas-