I don't know about an 860, and not sure what the lift capacity is for my '65, 3 cyl. 2000. But, my uncle made me a scissor lift to do what you are thinking. Length was maybe 36" - 40". It didn't have enough hydraulics to lift my 500+# bales.
There is a way to calculate how much lift is lost, for every inch/foot the load is behind the lift arm point, but have no idea how to calculate. But I do know the lift force is reduced greatly.
I ended up modifying an old hydraulic pallet jack to 3 pt., and attached a bale spear to it. I ordered a larger diameter hyd. cylinder from Surplus Center. The pallet jack cylinder was only about 3/4", and the one from SC as 1-1/2". The original cylinder wasn't big enough to lift the bales, but it had no problem with the 1-1/2" bore one. Got by with it for 4-5 years, until I bought a Bobcat, and added a spear to it.