Spacing before and after barlines

[Basil Crow]

Dear list,

I am using invisible barlines in the middle of a line in a score. I  
would like to completely eliminate any effect that these invisible  
barlines have on note spacing. I know I could just remove them, but  
there is no way to determine which ones would fall in the middle of  
the line and which would fall at the end of a line without actually  
running LilyPond -- an undesirable proposition. Therefore, I want to  
keep them in place in the middle of the line but just eliminate the  
effect they have on note spacing.

I have tried the following:

 \override BarLine #'space-alist #'time-signature = #'(extra-space .  
0.0)
 \override BarLine #'space-alist #'custos = #'(minimum-space . 0.0)
 \override BarLine #'space-alist #'clef = #'(minimum-space . 0.0)
 \override BarLine #'space-alist #'key-signature = #'(extra-space .  
0.0)
 \override BarLine #'space-alist #'key-cancellation = #'(extra- 
space . 0.0)
 \override BarLine #'space-alist #'first-note = #'(fixed-space . 0.0)
 \override BarLine #'space-alist #'next-note = #'(semi-fixed-space .  
0.0)
 \override BarLine #'space-alist #'right-edge = #'(extra-space . 0.0)
 \override BarLine #'thin-kern = #0.0
 \override BarLine #'gap = #0.0

But there are still "rivers of whitespace" where the invisible  
barlines appear in the middle of each line. Could someone please help  
me find the right property?

Thank you,
Basil