inter staff spacing

[Hugh Myers]

Given:

\version "2.13.7"
\header {
  tagline = ##f
}
\layout {
  \context {
    \Staff
    \remove "Time_signature_engraver"
  }
}
\paper{
  indent = 0\mm
  paper-width = 3\in
  line-width = 1.5\in
  paper-height = 5\in
  print-page-number = ##f
  after-title-space = 0\mm
  before-title-space = 0\mm
  between-system-padding = 0\mm
  between-system-space = 0\mm
  between-title-space = 0\mm
  head-separation = 0\mm
  page-top-space = 0\mm
  ragged-last-bottom = ##f
}
flash = {
  e,4 s2.
  \pageBreak
  f4 s2.
  \pageBreak
  g4 s2.
  \pageBreak
  a4 s2.
}
{
  <<
  \new Staff \relative c' {
    \set Score.barNumberVisibility = ##f
    \flash
  }
  \new TabStaff \relative c {
    \flash
  }
  >>
}

How do I control the distance between the staff and the tab staff. I
believe it is distorted because there is no other data on the page
which invokes some sort of stretching algorithm. Is there a way to
adjust this? I've played around with \override Staff.VerticalAxisGroup
#'minimum-Y-extent to no avail(I can't claim that I 'played' either
correctly or in the right place).

--hsm