I am reviewing my previous messages. As the concepts in this subject are 
a subtle matter, I would like to say that when I wrote, in my first message

\fam:enc   \fam:size 

I meant \font:enc,   \font:size,

and also, in my latest message, where

\cmr/shape   \cmr/width   \cmr/axis

it should better be \cmr:shape, etc.

Javier A.