Hi again,
I've already made some progress and was able to get a functional version of "my" Balanced Expanded mod, using PvK characteristics settings and traits and all the rest from Expanded. That is quite close to my "dreamed" SE4 setting
I've yet to review the AI files to have the AI races getting proper characteristics/traits, but am not sure of haw to proceed ... Too bad PvK didn't make them !
Thanks for the insightful advice Fyron !