[travelin texans]

Just realize that every pound you add, whether people, pets or helper springs, comes directly off of the already limited payload of a 1/2 ton truck.
With that rv you're already at 800+ lbs of tongue weight + the weight of the hitch off of whatever the the yellow sticker states on the the driver's door jamb.
If I recall GM is now listing tow weights for "conventional trailers" & "gooseneck trailers" on the door jamb, you need to also realize that those ARE NOT RVs. The manufacturer arrives at those weights using "conventional" trailers where the weight can be placed directly over the axles lowering the tongue weight considerably, you're unable to do that with a RV. The average tongue weight of a TT will be 12-13% of the GVWR posted on the front corner of a particular rv.
All this to say adding helper springs may reduce the sag, but does nothing to increase the payload of any truck, but rather reduces it due to the weight of the added equipment.