? Valvetrain Geometry ?

Pishta, Lash caps will add surface area and as a last resort they could be used. They require matching retainers and only give the rocker tip more area to sweep. With roller cams that is sometimes necesary. But adding area for the sake of keeping the tip away from an edge, is not doing anything to correct the actual path the tip is traversing. So your instability and odd angles are still there.