Built an f-stop enlarger timer and want honest feedback from people who actually print

I have built two DIY projects of that kind. The first version had an encoder wheel for the base time, I very soon changed that for two physical buttons. It's much easier to press a button four times compared to finding four clicks on an encoderwheel and there is no good visual feedback because the times change in a non-linear way...

What I added to my timer and really love, is that they also act as a dev-stopwatch once the exposure is complete - I find that very convenient, saves spaces and an other press of a button...