Available font sizes in Lilypond preview

When doing Lilypond print preview, is it possible to use an arbitary font size of, say, 14 or 15 points ?

The available pre-sets for font size include 11, 13 & 16 points. 13 pt gives me a score that is 2 & 3/4 pages and a little hard to read, while 16 pt gives me about 5 1/2 pages which is kind to the eyes but wastes a lot of paper.

Are the font sizes set in an .rc file somewhere and can the user change them ?

I'm using RG 1.7.2 on Kubuntu 9.04 with an old SB "Platinum" soundcard & right now I also have no sound output. There used to be, back in 8.10 so I guess I'll fix that eventually. It's not the main problem for the moment.

But fitting my score tidily into 4 pages would be nice.

Regards,

JohnC