2006 F53 18K Lbs. chassis. Normal rolling weight is about 15.5K Lbs. Installed bags on all corners this past winter. Helped slightly with the ride but Koni shocks on the front and shifting the sway bar end points did more.
My set up still needs work as I have the front pair and the rear pair cross connected rather than independent. Suspect with the cross connect I'm pushing air around left or right and possibly reducing the effectiveness of the individual bags. Once that point in the project is complete I'll get the ride height set properly with my load and reevaluate the overall effect.