Not exactly sure what he has going on there, but for both of my TLF pellet reactors, all I did was remove the short top plate inside, flip the long tube over, put a mesh screen over the red plate, and a short piece of clear tube inside to connect the long rigid tube with the plate to the inlet on top. Then put a MJ1200 on the inlet, and you're good to go. My pellets tumble like crazy.
Here is a similar mod, although mine doesn't ruin any of the parts, so you can use them later.
http://www.youtube.com/watch?v=Kh7LZExaMrA