Mount whatever back towards the stock. I have run a Mark 6 no issues. Currently I think there is a Trijicon 1x8 on it. No issues. Any platform with a large, heavy bolt carrier will make you need a good optic and good mount.
I have tried them all. Have many Aimpoint models. Have two of these PA.
one in 5,56 and one in 9mm. All are good to go. I have not tried the lower end SLX.