A good friend of mine has timed his CD20 by the book through dial gause, also did the old 2C i have in my 82 corolla. It works wonders if done properly. By properly i mean, other specs (Injectors and Pump pressure mailnly)are in check and are not done the desi way.
A reasonable chinese gauge costs around 5-6K with adaptor.
BUt you have to make sure that CSD is working fine, also it has to be blanked while setting timing by gauge.