Ok great, thanks. 80x15mm sounds good, I was thinking os something around that size so good to have a sanity check on that. I'll probably mount a lightweight skid plate/sump guard to these bars too, to add a bit of protection from brash etc in the woods.I used 80 mm C channel. That's what I had at the time. 80x15 mm flat bar would be a great choice too. Your tractor is pretty much the size of mine.
It's holding up great. I use it to load logs on the dump trailer with the forks, move dirt, tons of dirt. To be fair, it does sit a lot out of the tractor but when I need it, I really need it and gets used a lot.
About the only thing I would change now, was to use smaller bore cylinders. 50 mm instead of 60mm. When I built it, I tried to match, more or less, the capacities of the factory Branson loader. I really don't know why since I never push a loader to the max capacity, maybe 3/4 of the capacity at most. So the smaller cylinders would provide less lifting capacity (I'm good with that) but more speed, which I prefer.
Glad it's holding up well, looks like you made a brilliant job of it. Ah I see, it's all a balance. I usually find I end up using things to their capacity and it can be a bit hard not to. Say if theres a big log that the digger or tractor will just about lift, but I do feel a bit of mechanical sympathy and keep stuff greased.