Best way to vary rep range on an upper/lower split

So I'm currently coming towards the end of a full body routine (3x8 for all exercises) and for the next 8 weeks will do an upper/lower split training 4x per week. For this routine I want to use a variety of rep ranges and I've got a couple of different upper/lower splits that I've used before. My question is: What is optimal, to vary the rep range workout to workout, or to work with different rep ranges within a workout?
 
For example, I could run a heavy, medium and light day on an upper lower:
 
U 5x5
L 3x8
U 3x12
L 5x5
U 3x8
L 3x12
 
etc, etc.
 
Or, I could do something like:
 
Upper
 
Bench Press 4x6
Pendlay Rows 4x6
Incline Dumbbell Press 3x10
Pull-Ups 3x10
Lateral Raises 2x12
EZ-Curls 2x12
 
Lower
 
Squats 3x10
Deadlifts 1x5
Calf Raises 3x15
 
And then each workout switch about which exercises get hit by the lower resp and which get hit by the higher reps.
 
Would one method have any distinct advantage over the other?

I think your h/m/l set up would be better, doing the same with my FBR ATM and going very well, the light days almost seem like a deload after heavy days