Hi Gretchen,
You should check out
Salman's tutorials here on Flourish. You won't be disappointed.
I have found the best material on spacing to come from
Recueil Méthodique de Principes d' Ecriture "A Methodical Collection of Principles of Writing", P. Meyrat .
While it is slightly different in style from the Engrosser's Script in the Zanerian, its principles are strong. In terms of spacing between letters and the understrokes and overstrokes, Meyrat's explanation is the only one I have found with any sort of method to it.
All measurements are relative to the x-height. So the width of letters is roughly 1/2 of the x-height. This is also demonstrated (although not explained) in the Zanerian manual (see image below). However, Meyrat measured the width at an angle.
This is where it gets tricky... in reviewing much of the old texts and newsletters, the general guidelines are for equa-distant spacing. Lupfer specifies, "spacing between the shades" making note of two exceptions, from v to i and from i to x. However, that isn't as helpful for curved letters and over/under turns.
Meyrat's guidelines are:
1. For two straight strokes such as in diagram A (my version attached below), the space is 1/2 he body (x-height).
2. For a straight stroke to an oval, slightly less then half (B).
3. For an oval to oval (C), it is even less than B.
4. For an underturn/overturn, it is about 3/4 of the body.
Also on that example, is an example I measured from Lupfer and one from F.W. Martin.
I hope that is helpful!
