Vince, respect for you mentoring kids in the gym about training, your life long commitment to training and giving bodybuilding a crack but...
* You will never achieve a better body than you had in 1970.
* Your measurements are influenced by muscle maturity, glycogen levels and the increased adipose fat.
* There is no doubt that if you trained from 1960 to present, at exactly the same body fat level and weight, that you would experience a bell curve in your muscularity and measurements.
You are insane to think you will look better than your 1970 showings or that your lean muscle % will increase compared to that time.
I am 21 and I know this, geez.
You have a 'good build' for a non drug abusing, natural 69 year old but you would look tons better with even minimal amounts of testosterone. Let's leave it at that.