> Try double checking the reference lines, make sure the centerlines are
> square to the sheer lines, etc. If the reference lines are good, all I can
> recommend is patience.

What I did was clamp a level vertically, lines up with a gridline on the face of the form. Next, I clamped a temporary cleat on the back side that rode on the cleat attached to the strong back. Next I centered the form horizontally then using wedges, I lifted the form until it was centered vertically on the strongback. Lastly I rechecked the horizontal centering and the level. Once all were properly in place I locked it down with sheetrock screws, rechecking after each screw placement.

Greg