I would talk to Bob Clark,he breeds Rocks,and has always been straightforward with any questions I've asked him.I had the pleasure of working with a docile Rock,at a reptile exhibit.The staff there were terrified of her,and swore that she was "evil".This girl was over 15',and since no one else vollunteered,I said I would handle the snake...to make a long story short:I opened the door to her cage,she slowly came out to meet me( I had observed beforehand,that the snake was not breathing heavy and showed no interest in my presence)she smelled me a little,I gently picked her up and from then on we were best friends!LOL! I later found out that the staff at this place had always grabbed her behind the head when moving her.I never had any problems with her,but she continued her aggresion towards others who tried to handle her.I've also heard from other people,that Rocks usually calm down the bigger they get?
This is just my experience with one,but maybe this will give you some hope towards finding a tame Rock!