I have the RPG Stage 3 rear suspension with Deaver +3s and I want to use the air bumps for towing a travel trailer with a 715 lb tongue weight. The standard Fox air bumps that come with the Stage 3 kit are 2.5”. I have the 3” bump extensions for towing short distances, but I am considering the taller 4” air bumps for longer trips. For anyone who has them, I would like to know how much longer the 4” air bump are vs the 2.5”? Are they exactly 1.5” longer or is the top part longer as well? I sent a couple emails to RPG, but I have yet to hear back from them. For reference, here is my RPG setup with the standard 2.5” air bumps.