Compression test:
Measure with a micrometer
Mark with chalk
Cut with an ax

Basically, a big waste of time and effort. Go directly to the leakdown test- - - -do not pass GO- - - -Do not spend $200.00. Get some accurate results instead of a guesstimate about what's happening!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!