Here's a suggestion for ya (found this page by a post on FB where it's been around a time or six)
Get about 6 T's (at least 4) for each float set, and near the top and about 2 feet up from the open legged bottom put the T's in on each side, with a cross piece in the middle. Will add more support to the piping and a lot of structural support. In your trailer, it looked like they would also stand up on each side of the main load so not being able to stack them would still work.
Someone else also mentioned about pressurizing the tubes, really wouldn't be a bad idea, give you more buoyancy for sure. Just have to add about a 2 inch dia piece on a cross bar with a T in the middle of it and put a reducing coupling in it, then a brass ball valve with an air line male end to it. Then you can charge it and shut it off and have some extra flotation. Build the decking around it to protect it and it should work. Could always for grins and giggles get a small tank of helium and fill it with that if you dont inhale it all while making the mods HAHAHA
Another idea would be to fill the tubes with foam from old couches, chairs, swim noodles etc... anything that floats would work inside it, and will provide a slight safety margin should you rupture one of the pipes. Oh the ideas are becoming endless..... bbq grill on deck... an in the water cooler between the tubes...
GREAT idea.. might have to try this myself in the back waters of SC.
