Replacing Column Switch on 79 Spider

["Rex" <rexcars@domain.elided>]

The time has come for me to replace the column switch on the 79 Spider.
The symptom is that the quarter lights and dash lights (and the green
light on the dash that tells me they are on) all refuse to come on
reliably, although the headlights work fine.  Sometimes when I wiggle
the light control stalk, the other lights come on, but usually not.

The sort of good news is that I bought an original Alfa column switch
some time ago. The bad news is that the part I have it the three-stalk
version for the spiders after 1979, not the two-stalk version on my car.
The extra stalk controls the windshield wipers, as I understand it, and
the two stalks on the left work the same as on my car.

I noticed that Re-Originals has NOS column stalks for my car for around
$400.  I can't see fitting a NOS unit to this car.  The NOS stock pile
is finite, and this car, while a fine driver, with over 120,000 miles on
the clock it is no show car.  So I must make the three-stalk unit work. 

Here are my questions:  should I simply amputate the extra stalk and put
the new column switch in the existing housing?  If so, does anyone have
any guidelines on how the surgery should be performed?

Or should I cut the existing housing to create a clearance for the extra
stalk? (This sounds like a bad idea to me, since the cut will surely
look wrong.)  

Or can I get a used shroud from a later car and will it fit to my car so
that I can use the three-stalk unit without modification?  I'm worried
that the lock position or something else may have shifted in a way that
forecloses this option, as it invariably does.

Also, if anyone has any insights on whether the new column switch will
accept the wiring plug blocks now in the car without change or what work
will be required here if they do not would also be appreciated.

Rex in Averill Park
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