you don't want any side to side play on your ink form rollers. This will cause your hangers and latches to wear out. The major causes of your streaks on a QM46 would be rollers maxed out of adj., Ink dist osc drive cams being worn or the roller end play you are talking about. For the end play you can use a feeler gauge next to the roller bearing to measure and in stall roller shims based on your measurement. Try to use shims on both sides as even as possible. Install forms back in press with out the transfers and idle press. Watch for side to side play again and correct. If you like give me a call!
Stan, Intermountain Press Service 720-285-9485
PS. I also have numerous new and used parts for your QM46