Which way would stiffness and comfort go though? Because on the one hand, I'd expect smaller triangles to be stiffer, but then a longer seat post and a steerer with spacers probably not so much?
A smaller triangle would be stiffer laterally (everything else being equal), but longer seatposts are more compliant. So in theory the smaller bike will be both stiffer and more comfortable.
I very much doubt you (or anyone else for that matter) would notice though.
Which way would stiffness and comfort go though? Because on the one hand, I'd expect smaller triangles to be stiffer, but then a longer seat post and a steerer with spacers probably not so much?