Units and measurements and such 2.79 and 2.80 I am trying out both 2.79 and 2.80 and notice the behavior being the same.

I set the units to imperial and then changed the size of the default scene cube to something reasonable like 5cm. Then I applied the scale. My goal at this point was to make a radial array of 4 items, so I moved the cube 10cm on the x axis. Then I attempted to add an EMPTY cube which seems to come out huge.So I attempted to resize it by changing the dimensions, but it seems that I can put all sorts of numbers and units in the dimension boxes and in response blender just changes these values to some random number/unit combination even so far as up into miles and km. 

It also seems odd that though I can choose units such as mm or inches, when looking at things the dimensions are shown in whatever blender seems to be in a whim to show, such as "thou" or "ft" with lots of decimal places. 

Either:
 1. there is a bug, and it carries over between 2.79 and the current beta of 2.80, (my gut tells me this is unlikely)
or 
 2. I, personally, and not handling units correctly perhaps missing a step somewhere. (as a n00b this would be my guess, since it seems pretty complex of a program)

If I am just doing it wrong, can someone point me in the right direction for how to do it right?
I don't see units other than 1 in 2.7 when setting the scene scale; I don't see mm or centimeters or meters (in the properties panel > scene tab)?  


  I can put all sorts of numbers and units in the dimension boxes and in
  response blender just changes these values to some random number/unit
  combination


Blender adjusts from Meters to Centimeters to Millimeters as needed I think, eg.: when you scale from 99cm to 100cm it changes to 1m automatically (in the N panel). 


  Then I attempted to add an EMPTY cube which seems to come out huge.So
  I attempted to resize it by changing the dimensions, but it seems that
  I can put all sorts of numbers and units in the dimension boxes


I don't see any dimensions boxes, just "scale" in the N properties panel, and "size" in the "empty" data tab of the properties panel.  I did notice the scale seems to be double what it should be, ie. mesh cube was 10cm but the empty cube was the same size, but says 5cm.  May be a bug or maybe a sort of radius measurment (measured from the origin)? Idk.
GL OP : )