flektogon question

Now that we're on the topic of the P6 Flektogon, I've got a question on
focal lengths. I'm looking to twin two P6 cameras for stereo photography
and I need to have matched lenses. Does anyone have an opinion on the
variance of Flektogon focal lengths? Would the Arsat 45mm lenses be more
consistent? I had thought that lenses with five or more elements had to
have a small variance on the focal length out of engineering necessity.
Much thanks,
Steve