Thanks for the responses so far. Here is a section from the FAQ section on the RH Designs website:

http://www.rhdesigns.co.uk/faq1.html

"Why can't a Vario connect to a ZoneMaster?

The Vario reads the lamp output and adjusts the exposure time to compensate for variations, so for example if the lamp output falls the exposure time is increased. The ZoneMaster, like any exposure meter, also reads the lamp output and if it falls, the meter will suggest a longer exposure time (all other things being equal). Consequently, the combination of the ZoneMaster and Vario will over-compensate for lamp variations. The ZoneMaster relies on a constant lamp output in order to determine the density variations in the negative correctly and thereby calculate the tonal range. The Vario does not have a connector for a ZoneMaster as a result. "

The Analyzer docs say that the unit will handle the power requirments of a cold light:

"Switching capacity of 750 W (500W for 115v versions) handles most enlargers, including cold-cathode types."

Which isn't quite as clear as it should be, but obviously states only that it won't blow the timer out (like other digital timers could).