I've got a Braber brand QH, which is pretty much the same el-cheapo that Harbour Freight sells. I've got my upper hook set at the 15" mark from the lower pins. I had already built a
ballast barrel, and LPGS to fit the 15" dimension as that is the same as my Kubota snow blower. Had to modify the lower pins on the blower as they were 1/4" too wide.
The fun part was on the Braber box blade and rotary cutter. Had to cut/weld the lower links on the BB to narrow them 1/2" each side and made a custom mount for the upper pin. That was a pain to get something to fit that according to their own catalogue fits. On the rotary cutter, I moved/flipped/adjusted the existing parts to make it work without having to cut/weld anything but it took a while.
I'm in the process of building a logging grapple and made it to fit. The only thing left is to mod the wood splitter and the rear blade (but I haven't used the blade in a couple years)
Having to move the upper hook to me completely defeats the purpose of having a QH. Everything is getting modified or built to suit the one hook position. A couple of them fit quite tight with the bolts on the upper hook. Welding it in place makes sense to me, I'll never move it. Why that didn't occur to me, I'll never know.
To the comment about side forces springing open the hook with the modified pins, I fail to see how that would be able to be applied. The implement would have to be twisted in the lower mounts for that to happen.