Speaking my language, brother. Ha.
I’m working my way towards collecting all the books I I can from superstrengthbooks .com. Reg Park’s Strength & Bulk Training for Weight Lifters and Body Builders popularizing 5x5 was published in 1960 and summed up pretty well here:
I also have The Iron Man Barbell Course Number 1 and Dumbbell Course Number 1 (written in the '40s/'50s), laid out pretty similar to what you wrote - full body, three days a week; big, basic exercises with a few standard isolation lifts; typically focused on shorter/under-60 minute workouts; using specialization phases for specific body parts as needed.
One of the specialization routines he recommended back in 1955 is actually the “Hourly Workout Program” where you spend 6-8 hours training a lagging bodypart on the hour and on the half-hour. Poliquin and others later re-popularized it as the One-Day Arm Cure.
I also have some books from Harry Paschall from 1950/51. Again, same overall stuff (full body, training every other day). He did mention beginners doing upper body stuff starting at 5 reps, adding 1 rep every third workout until you hit 10 reps, then adding weight. For lower body training, start at 10 reps, progress the same and add weight when you get 20 reps.
John McCallum’s another great writer from the 1960s and his book Keys to Progress is a collection of his monthly column from Strength & Health magazine. One of his routines:
Yeah, almost like doing a lot of hard work, eating a bunch, and resting on off days can cover a lot of ground. Who’da guessed.
Different writers/coaches had a few different methods, but generally, the overriding idea I’ve read from that era is to stick with what we’d call today “technical failure”. If you can’t get a rep with acceptable form, end the set.
There were likely some exceptions, but that seems to be the most common approach. Grinding out ugly reps wasn’t really a big thing.
A couple of guys talked about their old school days here: