I have my VX mirror pivoted all the way up at the glass and pointed down/ out at the mirror, this places the mirror near the roof of the VX, and improves rearward vision.
On other cars I've owned, I have re-glued the nub on the glass higher. Another option I have done is to mount a multi-mirror to the visor area. this works great but you lose your visors (and map lights). Multi-mirrors work great for blind spots also.
As for heads hitting the grab bar area, only lowering the seat(s) will help. A future project on my list.