Cyril, you have to much energy.:laughing: Actually I take that back, you can not have to much energy. You must have a lot of energy. :thumbsup: With the design of your blade, I would first flip the cutting edge and see how much difference that makes. I think that you will be surprised at how much more dirt you will cut with that other 1/2". If you need more than that, maybe start adding weight. The blade is not designed strength wise to handle the weight though and with the size of your tractor, I would see blade failure in the future. My thinking is that if anyone needs to add weight to an implement, then they need a different implement.
I know that a HD blade is costly, but as most of us know, you get the tractor, you need to get the size implements that fit that tractor. A good match for your tractor would be a Land Pride RBT4096, might be able to get away with an RBT3596, but I would get the 40 series.
Hope all works out for you, keep us informed.