Bad idea generally since the problem was the outer "Lip" of the derailleur which tended to hit the inside of the crank arm (we've all seen examples of this gouging on various crank arms just from badly set "normal" derailleurs too).

I think a greater issue would be to find a correct length axle (and cups) to accommodate the additional inner chainring. For some reason known only to Campy, their triple cranksets always used the "thin" (Record) cup sets rather than the "thicker" (Nuovo Record) cups - which were the ones with the water-shedding "rifling" in the axle holes. Later triple axles were longer than the earlier ones too.

So, what you really should look for is a thin cup set and a later triple axle. If you have thicker cups, the longer center section of the triple axles would simply not fit in the NR cups which is spaced for a shorter 49 mm center section.

The later axle would be stamped "68 SS 120 X3 (+1.0 +1.5)" or simply "68 SS X3" and the sections between bearing cones would measure 28-54-38... versus 27-54-35 for the earlier axles which are ONLY marked "68 SS 120 X3".

If it is of any use... you may be able to use a Sugino "Maxy" axle marked "3TB" which measures 32-52-39 ... although the tapers may push the crank arms outboard slightly..(but maybe not a bad thing in this case).

Good Luck