A family of grammars for Voynichese

[Mauro]

I would add another variable, the total coverage C1: the summ of all instances of every word type the grammar generates divided by the total number of existent words.

Yes, I think I understand what you mean with 'C1'. I agree that a grammar is better the more it generates word types that are the most frequent in the text. I used the rank of the 'first missed word' (in effect, a proxy of C1) as an additional datum in my comparisons in the first posts. So C1 (or the rank of the first missed word) is indeed very much interesting. But it doesn't help in solving the problem of the "One slot * All the words types" degenerate grammar (C1 = 100% in that case), which is fundamental. But for further refinements, sure.

Some words have few instances and reducing the size of the slot grammar may reduce E significantly with a small decrease on C1.

Yes, but this is akin to what I referreded to as "Increasing efficiency... by judiciously decreasing the coverage". Ie. by dropping 'cfh' from a grammar the C coverage will decrease just a little, while efficiency will increase (probably) proportionally more, and the same holds for the 'C1' coverage (which will decrease even less). But I find this approach (and the other approach that can be easily used to pump up efficiency: defining more symbols) to be little useful, just a pointless exercise in optimization.

It is important to search the maximum amount of total words generated with the minimum size of grammar possible.

I agree on the importance of efficiency, but the whole main point of my post was to show that using coverage and efficiency is as much flawed as using coverage alone (and consequently the 'F1 score' is fundamentally flawed too, just for this reason. It then has another big problem, but that's another matter, less fundamental).