Seems to be working pretty well, but you might have problems with wood compression if you decide to add another set of wing. It looks to me if you add more wings, they will have to be added above the current wings. Your current wings are sharpend on the top side only. This will force the splits up, which you can see in the vids. An additional wing above will not allow the wood to rise/spread and compress the splits. I made the same mistake. I ended up cutting the bottom wings off and flipping them over and the top wing is only sharpen on the top side, same way your current wings are, and angled up at the back to allow the wood room to pass between the wings. I still see compression on really big rounds and think I should have angled the top wedge into a Vee shape, instead of having both wings welded at 90degrees to the main wedge. I have a 5in cyl and can force the wood thru the compression, but if I ever break the wings off, I will probably change the top wing to a vee.
It is a troybilt tiller I converted to be a tater digger. Its made to just scoop under the tater hills and roll the taters out of the ground. The troybilt tires couldnt get enough tracton to pull the vibrating digger thru the soil. I took some old trailer hubs and made adapters to bolt the tires off my Steiner tractor on it, hopeing that would be enough to make it work. It didnt, the troybuilt tiller is just to light and it will spin when you lower the blade into the ground. I am afraid to add any weight to the machine for fear the gear box wont take the pressure. I have all the tiller parts and plan on just turning it back into a tiller.
