Making mail compose fonts larger

[bobinsky]

Thanks to a post on this list I discovered the rules option of making
incoming messsage fonts larger. Now, is there a way to this while I'm
composing without changing the size of my default font that will
actually be sent (Arial 12, which is too small for my old eyes)?
Something like using "page width" and "normal view" in Word or clicking
on the "increase font size" icon in Safari.

Thanks!

Eric B.