[phenixbb] most appropriate map for ligand fitting/interaction with FMN

I am refinig a structure at 2.1 A. I have 2 questions: a) Is the best way to identify a ligand refining the protein and water molecules and at the end looking at the 2mfo-dfc and mfo-dfc maps? Or looking at a SA composit omit map? b) In almost every map i look at during refinement I see density that smears/joins my ligand (cyclopentenone type molecule) and flavin's isoalloxazine ring. Has anyone ever seen that? they seem to be 3.1 A apart? Thanks -- Yuri Pompeu