I dont have much time under my belt as a pump operator, but has any one else noticed a change in slump when you have the truck in a Z formation close to the truck vs. a R and F close to the truck?

No,

I have noticed that it is almost impossible to keep a 'full' 5" hose with a R&F in that position due to the fact that the concrete is falling twice as far [with the same size boom] with the R&F. What may be perceived as slump difference could in reality be a "splatter" and separation issue

I find, on a roll and fold, if you put the tip section at a 90 degree angle relative to the third section, it will help keep the hose full. 

if you want to keep the hose full (bob)you should speed up the pump i dont have any problem

do you really need a 5" hose on there probally should'nt be anyone holding it if you want to keep it full,instead use a 4 1/2" or 4" hose

Now we are back to the old 'different parts of the country' meaningless part of the discussion.

5" hose & rnf = full rpm, full tilt to keep up with gravity.