Zip, your much more of an expert on stuff like this than me, so I'm going to try to learn from you.
I would have thought that the bracket position wouldn't make any difference to how much lifting the blade would pry up on the track frames. It seems to me that when the blade is on the ground, the center of gravity (CG or balance point) of the track frames would be wherever it is. Let's assume it is roughly over the middle roller and for purposes of this discussion, lets not worry about how the tractor interfaces with this system. The blade CG will be somewhere forward of that, since almost all of the mass of the blade is forward of that.
The weight of the blade, however, will be spread between the cutting edge and the ends of the push arms. The cutting edge will be carrying most of the weight and transmitting that to the ground. The push arms are attached pretty near the CG of the track frames, so when the blade is on the ground there is little influence over the resting position of the track frames.
When the blade is lifted, the lift mechanism transfers all the weight of the blade to the track frames, some through more weight being on the push arm ends and most to the lift mechanism brackets. This lifting causes the weight of the blade to apply torque to the track frames since the CG of the blade is forward of the CG of the track frames.
Where I'm confused is, it seems to me that the design and attachment points of the lift mechanism relative to the track frame CG doesn't seem to me to make any difference in the torque the weight of the blade will place on the track frames. Once the blade is off the ground and all of its weight is supported by the track frames, I would have thought that the torque applied, and the tendency of the tractor to nosedive, would be constant as long as the CG of the blade system remains in the same relationship to the CG of the track frames.
Under my assumptions, it wouldn't matter whether you put the blade lift mounts clear out at the front end of the frames, clear out at the back end, put them in the middle or hung them on a pole beyond either of those, for that matter. The torque on the track frames, the lift of the sprocket and the nose dive of the idlers would be the same.
I'll agree that the position of the lift mechanism relative to the blade CG and its position relative to the push arm pivots will have a huge influence on the force applied to the pins and bushings within that mechanism, the wear of them and the required hydraulic pressure to lift and get the speed required.
Maybe I'm wrong in some of my understanding. I am, after all, just an accountant and not an engineer or an operator.
I'd be interested to hear your thoughts.
By the way, I hope your shoulder is feeling better. I'm sorry you got hurt, but I'm glad that it has allowed you to spend more time on here, at least.