This is the base girth routine.
https://mattersofsize.com/topic/exclusive-5x5x3-mityvac-ssj-girth-workout-monster-girth.1818148/
I'll usually do 15 mins of ssj before the first pump set or until my hands cramp whichever comes first so I have great expansion before pumping.
I double or triple...
From my personal experience yes they can tell the difference. My avg girth is 13.5 cm~5.25 in. depending on eq of the day. When I have the time and opportunity I will do extended girth sessions and can get to 15 cm ~ 6 in. sometimes slightly over that around the base (Usually do about 1 hr...