I still have the question of why bother keeping consecutive residues together? As far as I can tell, it produces uniformly worse results than allowing them to be separate. Unless there is some advantage, it isn't something that should be there.I think we should separate the discussion for fine coarsening ( up to 5 residues) coarse coarsening ( more than 5 residues).For fine coarsening I think the helper function is fine and most restraints would work will well with it.
Coarse coarsening, on the other hand, is needed mostly for flexible chain representation for which we can not apply either of these methods, as we do not have a structure, and so I think that for now relaxing the restraints is sufficient.It also makes sense in the case where you have structures of some of the components, but not others and just want to preserve overall shape.