Pellet weight and pellet fit will also have an effect on recoil believe it or not.
This is more critical on a heavily tuned springer.
I think the theory being - too little resistance and you get 'slam', too much resistance and you get 'bounce'. The LGU's 2.7mm transfer port does help to eliminate slam quite well, at the expense of some efficiency.
Chrono'ing pellets at the muzzle will tell you diddly squat about how accurate they're likely to be. Setting your chrono out at 50 yards will give you a much better indication of accuracy.