Where do they put the stoker's timing chainring?
well track tandems and Rohloff Hub Tandems
all 3 chainrings can be on the Right, BUT..
derailleur bikes, the timing chain nowadays connects the captains crank.
to the left of stokers Crankset.. 3 on the right 1 on the left
the 40's~ 50s setups, there was often a really long final drive chain,
and the Captain had the chainrings on both sides of the spindle, then..
so in that situation, the stoker could be considered connected by 'their' timing chain..
current setups I'd say it was the Captains timing chain..
SO, The folly of universal generalizations, not
Always
tandems are commonly having 2 chainrings on the left..