Bottom line (so to speak) - the pool noodle concept works. Weight isn't the biggest issue. Drag and changing aerodynamics is a larger problem. But you have to ask yourself just what exactly are you trying to accomplish? Are you trying to retrieve a downed drone? Trying to get some shots with the water coming right at the camera? Wanting to take off and land in the water to prevent having to deal with the boat?
If you look at many of the videos you see a disturbing trend - pool testing but not open water experience. As you are doubtless aware, Puget Sound is not a pool. Even small wind driven waves or swell can upset a floating device.
I have my doubts as to whether a pool noodle equipped Phantom will be particularly happy in anything other than flat calm. But you would likely save the AC itself. Now, you can resurrect salt water infected Phantoms at least some of the time (notice the rather generous use of hedging here....) You're going to at least lose the battery. The camera is also likely to take a nice dive. The motors / motherboard can *probably* be resurrected. Absolutely no guarantees. YMMV. Professional driver on a closed course. Do Not Taunt Happy Fun Ball.
I have no experience with any of the commercial products. What I do is to attach a 'Getterback' rod recovery system to the frame (~$30). It is as small float with a 100 foot cord that is activated by water. The idea here is that when you dunk the thing, the float escapes and comes to the surface where you can retrieve it and pull the drone up. You will likely lose the above bits and pieces. You will likely save the video / images.
I also fly older P3Ps off the boat, practice hand catching and come back with the battery around 50% to give me *plenty* of time to land. If nothing else, it's exciting.