AllVol -- Thanks for the link, but it doesn't appear to come up correctly...the full URL didnt' come through, just the shortened version containing the "~"
Ron -- With only the 6 v supply connected, the junction of R2, R3, R4, and pin 2 (on your schematic), the voltage is 2.61 v. Connecting the single AA cell (1.34v) gives a reading of 2.85v, while connecting the flash leads (4.5v) gives a reading of 2.61v.
This might be obvious, but with the flash on and ready, putting a meter across the terminals gives the 4.5v, but naturally the terminals have to be shorted with a mimentary switch for the flash to fire. The electonics in the flash then take this voltage to zero after 90 sec. It is this voltage drop I am trying to capture and then have the relay energize at the moment, and then the reverse after this works. Thanks!