I assume that you will also be fitting a return spring, or are you trying to rely on the back pressure returning the lever to its normal position.
It doesn't need a separate return spring, there is a spring built into the MC. Hydraulic clutches & front brake MC's on motorcycles don't have separate return springs & they are only fitted to foot operated rear systems for construction & use regs'. The MC I'll be using is proven to not need any extra help on returning.
I've been to a bearing shop today & picked up an assortment of roller & plain bronze bearings. They don't stock plastics in such small sizes so I'll order an assortment off the net. I'm happy to experiment & the device will certainly gets lots of real world abuse during R&D.
This is the first time I've worked with bearings, I'm more interested in how to get the hole size right & how to keep it all working once it's all bolted up.
Any help appreciated.