The sled is made to become an integrated unit with the rifle; they recoil together. Unless you have a way of returning the whole mess to the same alignment, you might well have problems evaluating groups. The thing is designed for recoil reduction, not accuracy.
If you anticipate problems with recoil, make sure that the rifle fits YOU; I can't shoot most Win Model 70's because I am wide and have short little arms, anything bigger than a .243 smacks me hard. (I have no problems with most other makes, it is fit, not the actual recoil that cause the discomfort. I can shoot decent groups with my TRG-S in 338 Lapua because the stock fits me).
Next, fit up a decent recoil pad, then if more recoil reduction is needed, practice with lighter loads/bullets.
If you want to test the accuracy potential of the rifle, you need to go to a true machine rest.