[Leica] Optimizing (minimizing) filter inventory

[scott at adrenaline.com (Scott McLoughlin)]

I shoot almost all B&W with my two M6TTL's and a smattering of
Leica and CV lenses. I'm generally a fan of light green/yellow filters
for general B&W shooting, and have equipped my two "main shooters"
with these filters (B+W): Leica 28/2  E46 filter and CV  50/1.5  E52 filter.

My other two "2nd'ary shooters" are currently filterless: Leica current 
90/2.8 
E46 filter and CV  21/4  E39 filter,  although I do have a medium yellow 
E39
for the CV 21/4 and CV 50/2.5 E39 (when i want a smaller 50 shooting 
setup).
In general, for convenience, I imagine just snagging two more (E46 and E39)
yellow/green B+W filters is an obvious plan.

So now my real question.  I'd like to experiment with red and orange 
filters,
something I haven't done with my Leica/CV lenses.  I won't be using red or
orange filters for "regular" all-around shooting, so I'd like to avoid  
outfitting
each lens with both red and orange filters.

So, I'm wondering, with concerns for possible vignetting, I'm wondering what
"optimal" or minimal configuration or red/orange filters I might achieve 
with
stepup rings.  The current stable of lenses is:

CV 21/4 E39
CV 50/2.5  E39
CV 35/2.5 P-I (LTM) E43
Leica 28/2  E46
Leica 90/2.8 (current) E46
CV 50/1.5 E52

Any and all advice greatly appreciated. 

Thanks!

Scott