In case it helps anyone else in the future, I installed two DIY Knobsters using the following items from eBay.
(EC11EBB24C03 Dual Axis Encoder with Switch 30 Positioning Number 15 Pulse Point)
Compatible Arduino Nano V3 16Mhz
Terminal Mount block
They all work fine.
I also created a wiring diagram for myself to make it easier when I was installing because there is only a pin number table on the Siminnovations Knobster DIY Wiki page.
I sent this diagram to the support team at Siminnovations about a year ago because I thought they might include it on their page but they said it was “not good enough”.
There is still no diagram on the Siminnovations wiki.
Hopefullly my diagram will be good enough to help someone doing a DIY Knobster.
Feel free to pass it on