Both the 4point9 at 13g effective mass and4point11 at 18g effective mass will be fine for the Etsuro. Personally since you already have enjoyed the fantastic VTA on the Stogi S get the 4point11 if you can.
Going from the Stabi to either the R/4point or Reference 2/4point I think you will be pleasantly surprised at how much improvement you get over the existing set up.
I think the Reference 2 is better than the R for the reasons you have suggested - the Kuzma M is where the new DC motor hits its straps ( it has a bigger motor/bearing and platter than the R ).
If you need to squeeze the budget I would say go for the Ref 2/4point9.

