Measurements below for WSTT50:
>Does the nominal measurement accurately indicate the actual internal depth clearance as measured from the deepest insertion point out to the inner-most edge of the flange of the rubber end-cap coupler? (if not what is the actual measurement?)
Ha! Not at all. 6 cm.
>How much further can the eraser end of a pencil be pushed in once it lightly 'bottoms out'? (slightly compressing the internal end-foam)
Almost a full cm more. Difficult to measure as the inner foam is the large open-cell variety.
>How deep is the rubber coupler's microphone mounting flange? (same depth as the external flange around the outer edge of the rubber endcap?)
External flange where "MOVO" is printed is 17 mm.
Thickness of rubber that contacts the mic body is 1.5 mm.
That contact area is countersunk / beveled inwards towards the head of the screen 5 mm. Inner beveled area is 37 mm dia.
>What is the exterior diameter of the entire rubber end cap?
7 cm
>What is the overall external length of WSTT50, WST80 and WST100?
WSTT50 is 100 mm total length.