Is there any way I can issue a command to change the z offset during a print? That would be such a huge step for me because then I can tweak the first layer in real time through pronterface while its making the brim until I am satisfied with the first layer height, and I dont even need to kill the print and start over.

This would be a good thing. Other then that, I am still getting air prints as first layers when I walk away from my machine.