Maybe I'm just talking to myself here, but if anyone is interested in such things--
My Vari-Strobe started strobing a couple of months ago and then stopped working altogether. It was pretty beat up, so I just tossed it, rather than having it repaired, and as it happens, I found a Norman LH3b auto strobe head to replace it.
The Norman is physically a better design. The head tilts, and it has a solid flat base for mounting on a bracket (the GVI's was a little wobbly). The remote sensor uses a simple stereo mini-plug, instead of the 5-pin DIN connector that the GVI used. There's a little more space between the flash tube and the sensor, so there's more room for slightly larger reflectors without having to use a remote sensor cable.
The unit I have underexposes by about a stop. This is easy enough to adjust for (just set the calculator dial to one stop less than the actual film speed), but I wonder if a previous owner had it calibrated that way to use it as outdoor fill flash.
The auto function does work--I can change reflectors/diffusers or use bounce flash and come up with the same aperture on my flash meter.
The Norman doesn't have the auto-fill feature that the GVI had or the manually adjustable low power settings, but it does have manual fractional power settings down to 1/16, and it seems able to produce a flash of less than 1/16 in auto mode.
The GVI had no range setting, but the Norman gives you a choice of five overlapping distance ranges, and therefore more possible f:stops in any given situation, which makes up somewhat for the lack of auto-fill, since you could set the flash on auto to "underexpose" by whatever fill ratio you wanted and do auto-fill that way.