i think you should train all rep ranges. even if it isnt on the same day, or even in the same month (periodizing), you should hit everything, especially as a more advanced lifter.
if i do 1 body part per session, i usually hit extremely heavy low rep high rest sets in the beginning, and taper off into more volume.
right now i am doing upper/lower split, 2x per week, one time all strength, and the other all shorter rests and reps between 8-15.
you should also pay specific attention to your rests and heart rate. if you turn your weight lifting sessions into cardio, essentially, you will begin to burn more muscle than you gain. it is very important to experiment with your body and see how you respond.
the one thing i will emphasize, is to lift heaviest possible weight that you can control for your desired goal. if you are training in the 8-15 rep range, with a weight you can do 16-20 reps with, then you arnt lifting heavy enough and will not force adaptation