About AUTODOCK grid point

 Dear All,
 I have two questions about Autodock.
 (1) I am trying to docking several small ligands to a huge molecule by
 AUTODOCK. But by Autodock tool, I found the maximum grid point only can
 only be set to 126 in 3D. And I check the autodock manual I haven't found
 there is a limit about grid point. Did anyone have similar experiences?
 Could you please share them with me?
 (2)Does anyone have Phosphorus of ATP parameters?
 Thanks a lot,
 All the best,