[plt-scheme] Non-Integral Font Sizes in DrScheme

Is there a way to use a non-integral font size in DrScheme?  For
example, I want to use DejaVu Sans Mono at 10.5 because 10 mashes some
of the letters together and 11 is too big.  When I try to set it by
writing a non-integral value into the prefs file directly the default
value (on one of my systems it's 11, and on another 12) is used
instead.  This is what I do for GTK, both generally in .gtkrc-2.0 and
in Vim where I can 'set guifont=DejaVu\ Sans\ Mono\ 10.5'; as another
example in FVWM one can say 'DefaultFont "xft:DejaVu Sans:size=9.5"'.
As may already be apparent this is under X11.

Thanks,

-- 
Taylor Christopher Venable
http://real.metasyntax.net:2357/