Savage, I think what you are referring to is when I was doing relatively high frequency AND relatively high volume. I tried to do 7 total sets twice each day, 5 days per week and that was just too much for me (70 sets per week). I cut that back to 4 sets twice per day, 5 times per week (40 sets per week) and saw an immediate benefit. My ideal is probably somewhere in between.
For my next cycle, I am going to cut back to 4 times per week but keep 2 full workouts per day and add a third mini-lat workout in mid day.
It will look like this:
AM:
Incline Press
Chin Ups
Shoulder Press
Squats
Seated french press
Mid Day:
Pull ups
PM:
Dips
Seated Rows
Shrugs
Leg press
Curls
I say four times per week but if I can, I will do the routine 5 times per week. That way if I miss a workout here or there, I won't feel like I am behind in my schedule. My psyche sometimes benefits from these type of silly games to trick it into thinking I am ahead of schedule. That way I seem more motivated to stay ahead of schedule. It sounds stupid, and I think it is, but it seems to work to my benefit.
In all liklihood, I will be doing between 44 and 55 total sets per week, i.e., one set of each exercise.
I added the extra lat workout because my lats really benefited from the increased frequency and I want to push them a little harder to see if even more frequency will be better. If it does, I will probably rotate a different bodypart in each cycle to get that extra frequency periodically.
I didn't miss the isolation movements at all. However, I am adding in french presses and curls on this next rouitne to see if it makes a difference. I didn't lose anything without them and now I want to see if additional isolation frequency will be a benefit or be too much. Due to the lack of extensive research on hypertrophy and frequency, I find I have to resort to my own experimentation to see how I will respond. So far, the results are very positive. Of course, you do have to make sure you eat good and get enough rest or you will burn out.