It occurs 3 times per 1 revolution of the front ROTOR, correct?

When finding TDC will any rotor 1 face be suffecint or is there 1 of the 3 that is prefered?

 

TDC on a rotary is a little different than piston engines. We have different TDC's depending on how you look at it. Here's a link to Paul Yaw's site that explains it. It will take a little studying to figure out.

http://www.yawpower.com/dectech.html

 

Actually, aki11ez is correct. Every time the front rotor's face is closest to the spark plugs, the TDC mark on the pulley will be at the pin in the front cover (or 5°ATDC for a GSL-SE or later 13B). Yes, any rotor face on the front rotor will do.