[phenixbb] refinement

Hi all I do have very low resolution data (around 4 ang), what are the efficient way of doing refinement, either rigid body alone or rigidbody and tls or individual with group_adp. I did both, but not much significant changes in Rfree stays around 48/50%. Also I do have other questions 1. While doing rigid body refinement, phenix complaint about the special position and could not perform rigid body refinement, whereas individual site refinement is working fine. I do have to delete the atom in special position for rigid body refinement? Thanks