Running trills are jagged

[Dylan & Paula Nicholson]

Lilypond draws running trills by using a series of "r" glyphs from the feta 
font.
But these are jagged, like a mordent.  On all the scores I have access to,
trill lines are wavy/sinusoidal.
Is there a way of getting wavier trill lines?

Also, is there a way to get lilypond output at "actual size" (100%) 
magnification in Acrobat Reader to look good?  Certainly the default scaling it 
uses is pretty ugly.  At least on my machine, staff lines need to be exactly 
5.25 points apart to get even spacing and even staff line widths (it seems 
Reader uses 4 pixels for 3 points).