Enlarging Meter-Timer

This is not specifically a large-format product but aimed at analogue printing in general.
Having previously posted here about other products we produce at DLG Electronics and had some very good feedback, I’m inviting people here to have an input into the design of our next product - an Enlarging Meter-Timer - at the concept stage.
Here is the proposed product:
http://www.dlgelectronics.com/enlarg...ter_timer.html
There is a pdf download summarising the concept.
Any comments or suggestions on the design?
Would you buy it? Is there a market for it?
I’ll later be looking for a volunteer or two to trial a prototype - in return for comment and review they’ll get a free unit.
Thanks,
Dave.