So if i get your point here Mr.Dave, it gives me a conclusion like this:

IF I have +Y Restraint in my sistems in particular position, so does the gap and friction, first i'll run the analysis with Liniear analysis, if in Seismic case or OPE case i found that any of this support lift off it means that i have to build the case in Non Liniear analysis like COADE suggested. if none of the support lift off, so i can just do yhe Liniear analysis.

Correct me if i'm wrong.