Bert,
What you have was actually on top of my list of options..
The main reason I went with gears was I had them already :-)
Also, I wanted everything to be packed inside (because of transport.. While I do have a sort of semi-permanent site here in my Mt Waverley front yard, sometimes I go to Daylesford to friend's farm (very dark site).. and anything that protrudes out of mount would be in danger of being damaged.
I even considered internal pulleys (a bit difficult to assemble, but possible) but I could not find right parts for this (thin enough belt or chain was the biggest problem.. I was looking here:
https://sdp-si.com/eStore/. BTW, they have gears like I was using in my solution and I think originally they came to my junk box from those guys).
Anyway, this is an interim solution. If it does not work as it should, I will go with timing belts (like you have).