Enlarging tenuto marks

[David Sumbler]

I find that tenuto lines in Lilypond are rather too thin and short.

With the help of this list, as well as the Lilypond documentation, I am
gradually starting to understand more about how Lilypond functions.  So
I was reasonably confident that I could at least increase the font size
of tenuto lines to see if this would give me a satisfactory combination
of length and thickness.

I had a couple of false starts, because I found it difficult to
determine what the name of the relevant grob was.  But eventually,
having decided that the name is, in fact 'Script', I was almost certain
that this was going to work:

{ \tweak Script.font-size #6 g-- }

But it completely fails to change the tenuto line.

I see that the Snippets document has a couple of ways I could achieve
what I want, and they might be a better bet in any case for practical
reasons in the coding.

But why doesn't '\tweak Script.font-size' work?

David