SUMMARY
Plasma sizes applets inconsistently based on Layout.preferred(Height|Width) when adding them to the desktop

STEPS TO REPRODUCE
1.  Add an applet
2.  Try it another way
3.  Try it on another system
4.  and so on

OBSERVED RESULT
Applets size inconsistently, based on enough factors that it's impossible to tell what's causing what without diving into the code.

EXPECTED RESULT
Applets size to the same size, every time.