I bought some steel at lunch today. Little bike weighs 110 pounds. Big bike weighs 230 pounds. I'm guessing my new bumper/receiver will add 50-75 pounds behind the axle.
So for 2 bikes, thinking big bike up front, moving the little bike to the back. When it's just the little bike put it up front (already works fine), and when it's just the big bike then use the receiver carrier in back to offset some tongue weight with propane or something, or leave the camper at home and just sleep in the truck. Or just have it heavier up front. In my head all of these puts me within 100 pounds of a tongue weight I've already proven works without issue.