Hey Dale,
About your rest, I have read that if you drag them across the bench, you take a big risk of breaking the legs or leg. Otherwise they perform very well for the price. I would roll up a towel to rest the front of the gun on. This prevents some of the muzzle jump. Also, resting the stock in the exactly the same place on the stock helps the grouping.
If your group problem persists in the Whisper, it may be your pellets, try JSB Exacts, Crosman Premier Lites or Beeman Super Domes. I also find that Benjamin round nose are very good, especially for the money !
If all else fails, it could be your seal :0
Bill