Very interesting experiment.
WSMs, IMHO, tend to produce a drier product if used w/o a water pan.
I've cooked ribs on an indirect Heatwave, Masterbuilt electric, CookShack, WSM, ceramic cooker and Big Easy... I've found they all require a slightly different cooking technique. (It al depends how lazy I am <lol>!) But I never went to the effort of documenting the cook except for my own notes.
Nice job and great write-up. Thanks for taking the effort.
Mike