Small bathroom, the natural place for the tub/shower is against the exterior wall, replacing window, will tile up to bottom of window (~6'). The goal is to get the window as high on the wall as possible. The question is: what are my options for the header? Can I remove any of the top sill(s) and move the header up? Or, is the highest the header can go is to the top sill, removing the cripples? Sorry if I've got the terms wrong.