you know color chemistry is really easy... I've been doing E6 in a plastic dishtub with holes poked in it to keep the water level constant and controlling the temp with the sink
I taco dev 4x5 c41 and e6 in my paterson tanks.
And my quality control was much higher than the local "pro" lab, even after i intentionally threw the temps off 5 degrees to see what difference they made. Still came out beautiful.
The most expensive part of my E6 processor was the Weston thermometer.