OK, now that I have a proper keyboard...
I have a 4" Smiths RVI tach in my car, originally from an MGB. I also run a 123ignition electronic distributor.
The first thing to ask is, what sort of "electronic distributor" are you looking at? If it's a 123, or a Pertronix-style hall-effect kit then your RVI tach
WILL work in exactly the same way as with points ignition. Mine did, although age overcame it and it did eventually stop working although this was unrelated to the electronic ignition. If you're planning to run a Megajolt or other computer, it will
not work.
The way the RVI tach works is that it detects the current consumed by the coil when it charges between sparks, rather than the RVC-type which measures the voltage change on the negative side of the coil which is triggered by the points opening. Everything I read when I installed my RVI suggested that electronic ignition was too efficient and altered the charge timing of the coil in a way that the RVI tach wouldn't detect, but in my case with the 123ignition dizzy, that just didn't happen. The coil charged, and the tach detected it and it worked perfectly.
As above, my tach did eventually stop working but that was down to the germanium transistors which have a limited life and eventually die. I had mine retrofitted with electronic guts by an instrument shop, so it's now triggered by the impulse on the negative side of the coil (as per the RVC type) and not the charge current. Oh, and it's more accurate now
Hope that helps
