I should have looked in here earlier. If you ever get the chance have a look at some of Poliquins stuff Jim. It's all about variety, but in the right doses. Also, if you stretch properly you won't lose flexibility regardless. There are Mr Olympia's that can do the splits among other things. One of the Poliquin programs i made immediate gains on involved varied reps. You pick a heavy exercise for the one muscle and do 4 sets of say 4-6. Then pick another heavyish exercise and do say 3 sets of 8-10. Then choose a lighter type finisher for 2 sets of 12-15. If one was to do the higher reps first you would not have enough left when going heavier. Choose the exercises well tho. The BIG thing too tho is to vary the cadences. I haven't got my book handy but will try my best
An example
Chest
Flat Bench press 4 X 4-6 with a 3 second negative, 2 second pause and a two second positive
Incline dumbell press 3 X 8-10 2 second negative, 1 second pause and a one second positive
Flat flyes 2 X 10-15 1 second negative, no pause and try to thrust on the positive.
I made great gains with this training. Proper supersetting also had a great effect.