Some background. I use a Beseler MXT with a Zone VI (Aristo) Cold Light Head. I plan to upgrade soon to the V54 lamp. I have a Zone VI Stabilizer and A Zone VI drydown timer that has knobs that allow me to set it anywhere within a range of .1 seconds to 10.9 seconds. I've begun to practice rudimentary f-stop and split-grade printing. I would like to use a setup that is more amenable to f-stop and split-grade than I currently have. I understand that the v54 lamp will shorten my exposure times as the old lamp with a Y40 filter works for VC printing but with very long exposures. First question: Am I correct in assuming that in addition to swithcing lamps, moving over to an f-stop timer means swapping it for the Zone VI timer but that I will still employ the Zone VI stabilizer? I'm looking at both the offerings from RH Designs and from Darkroom Automation. Second question: Are there other manufacturors that I should be aware of? RH Designs' Stopclock Vario is designed for cold light heads and has "a compensating feature which measures the light output from the enlarger lamp and adjusts the exposure to compensate for any changes." Third question: Does this mean that it replaces the stabilizer as well as the timer? RH Designs' ZoneMaster II meter can be used with the Vario as a separate tool but not connected to it, as it can with their StopClock Professional. Their Analyser Pro encorporates both the timer and the meter. Fourth Question: Is the Analyser Pro compatible with my cold light head? The Darkroom Automation F-Stop Timer (with or without their separate meter) is a much simpler device and is much less expensive. Fifth Question: Can someone with some persoective on working with these devices tell me how significant a sacrifice one makes if opting for the much smaller feature-set of the Darkroom Automation products? Thanks in advance for any answers to these questions. I'm hopeful that this thread will be useful to other people that have similar questions about selecting an f-stop timer.