Best advice I can say is keep it in as close as possible and make the subframe heavier than you think. More weight is good and also adds stability. Plus keeping the loader in tight to the tractor gives lots of stability. I used 3/8" steel on most of the subframe. It's heavy but I can fill the bucket full of dirt (48") and there's absolutely no flex. The tiller would be a great counterweight as long as you have room to work. The advantage of a weight box is the ability to maneuver without hitting stuff with the monstrous tiller hanging out back. I made a Johnson loader fit my Massey 1655, similar sized machine, and love it!! Look under the Massey subforum for my thread.
As for the pump, mines direct drive off the crankshaft. I used a pump and bracket from a Case GT
to run my loader. Made installation easy. You might look into that or putting a lovejoy on your front pto
shaft to drive the pump. Good Luck and you will love it once it's done.
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