SR 4759 is the propellant of choice. It was developed specifically for reduced loads in the 30-06. The following page should give you safe maximum data:
http://www.imrpowder.com/rifle/3006_2_frame.html
Loads may safely be reduced as needed when this powder is used; but if you go really low, say below 600 fps, remember that if you drop a short charge you may lodge a bullet in the barrel.
Personally, I have had a great deal of success in using a "sissy" bag or shoulder pad as circumstances warrant.