Deaver's stage 3 Expeditions with or without air bags?

I'm thinking about going to Deaver's stage 3 expedition pack, currently I have a long bed 2010 Tacoma with new factory springs with Head Strong's 3 pack AAL's with Rough Country's 6" lift currently it's sitting level with 940 lbs. of constant bed weight without trailer weight the factory springs and the AAL's are straight as tooth pick's!
I want to add a heavy cargo trailer occasionally on city roads and travel backroads without it keeping it level and not raked. Should I add airbags when pulling the trailer and will the stage 3 rake it more?
Currently it has rough country's 2 3/4" lift blocks in the rear and the AAL's add about 1".
Can anyone recommend a set up before I pull the trigger on a $1,200 set of springs?
Check out the photo of the truck with a little sag with over 300 lbs. of tongue weight with 940lbs of existing bed weight the springs are semi straight but it's not going anywhere with
the trailer yet. Should I remove the lift blocks and mount the Deaver's directly to the axle then add the air bags Deaver stage 3 has 3" of lift I had read. Any advise would be helpful!