Q2f14v Secret Writings

[ReneZ]

Sorry, I got my numbers wrong!!
(This is what happens when working from memory and not checking).

When I started off with 15, it should say 18.

So here goes again....

The minim height of characters is typically 18 pixels.

This is the height of characters without ascenders or descends, so typically i , e , o  etc. and this does not vary a lot across the various hands.
The typical line thickness is around 6 pixels. The 7 above is close enough.

Expressed in mm, 18 pixels is 1.1 mm and 6 pixels is 0.38 mm.
The latter figure is right in the ballpark for modern technical drawing pens (You are not allowed to view links. Register or Login to view.).

18 pixels is also only 3.2 points. A point as used in font sizes is 1/72 of an inch.
The value given for a font is usually the height of a captial E or H (remarkably there does not seem to be a standard definition), which partly explains the discrepancy between this 3.2 and the normal point sizes we are used to (around 10). 

The Voynich writing is largely comparable to print using a 7-8 point font. A bit larger in some Hand-1 pages.