tremolo issues

[Justin Glenn Smith]

using 2.12.3 (as packaged with Debian stable), I get the following issues:

tremolo marks touch the half-note stems, and I would like them to stop short 
(giving an appearance similar to the tremelo marks for the whole note in the 
included file)

I get the warning message "weird stem size, check for narrow beams" for the whole note 
tremolo. If the note is lower on the staff, the message goes away. Is there some fix that will 
either take care of the underlying "narrow beam" issue on the whole note if it is a valid 
issue, or make the warning message go away?

following is a snippet that shows the behavior I am talking about:

\version "2.12.3"

vi  = { g!2:32
        % beams are too wide on the tremolo here, should not touch the stems
        \repeat tremolo 8 { f!32 e! } |
        % these overrides are make the marks line up with the notes,
        % they do not affect the "weird stem size" / "narrow beams" warning
        \once \override Beam #'gap = #1.5
        \once \override Beam #'extra-offset = #'(-0.5 . -1)
        % "narrow beams" bug here
        \repeat tremolo 16 { f!32 e!32 }                         | }

\score {
  \new StaffGroup <<
    \new Staff <<  \relative c''' \vi >>
  >>
}