How to fix bad overlap between normalsize and smaller note sharp, flat, natural?

[Pieter Terpstra]

Dear lilypond users,
How would you recommend to fix this?

Most kindly,

   Peter

Have an example here:
\version "2.18.2"

\relative c'' {
\key gis \minor
\time 2/4
<<  { 
   % Voice "1"
   \teeny
   g16 ais b cis d e fis gis | eis, fis gis a eis!4
   } \\ {
  % Voice "2" 
  g4 d' | eis,4 eis!
   } >> 
}