Slur position accounts for omitted stem

[Br. Samuel Springuel]

In the following snippet I've got two slurred notes that are fairly far 
apart.  This leads to one having a natural stem up and the other down. 
Naturally, when those stems are present, LilyPond should move the slur 
so that it doesn't collide with the stems, as is shown in the first 
Staff.  However, when I omit the stems LilyPond doesn't move the slur 
accordingly (shown in the second staff):

#(ly:set-option 'relative-includes #t)
\version "2.19.49"
\language "english"

music = {
    e'( b'--)
}


\new Staff
<<
    \new Voice = "mel" { \music }
>>

\new Staff
<<
    \new Voice = "mel" { \omit Stem \music }
>>

A bit of googling led me to this old thread:
http://lists.gnu.org/archive/html/lilypond-user/2011-12/msg00522.html

Here, three suggestions were made (updated for 2.19.53):
\override Stem.Y-extent = ##f
\stemDown (or \stemUp, by extension)
\override Stem.stencil = #point-stencil

The first and third don't seem to work anymore.  The second works, in 
the sense that it does something, but forces the slur and the tenuto on 
the same side of the note and so doesn't look completely pretty.

Some more googling led me to this issue:
https://code.google.com/archive/p/lilypond/issues/3760

Which is for 2.19, but is still 2 years old.  Has any progress been made 
here and if so what is the correct incantation to get nice looking output.

For the record, I think e'^( b'_-) provides the best looking stemless 
output and am hoping for some solution that would allow LilyPond to find 
this result automatically.
--
✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝
Br. Samuel, OSB
St. Anselm’s Abbey
Washington, DC
(R. Padraic Springuel)

PAX ☧ ΧΡΙΣΤΟΣ