Cool post. Fascinating premisis using a weighted fly and buyant foam as a sort of counter balace. I bet that foam catches alot of water sunk down deep on that weighted fly and creates alot of action. Pogo sticking across the bottom. I don't know what kind of dubbing he was using but I wonder if wrapping in some CDC into the fly would create little more "liveliness"? I'm thinking a good fly tier could take the idea and make lrg. variety of flies based on this. I'd also be curious if playing with creating different shapes via the foam might be able to give the fly a little more wiggle with the already up and down action its getting. Very cool & thanks for the post. I've got to get better at fly tying so I can start to experiment a little.
Get outdoors & have fun!