I built a three point forklift during Ag/FFA in high school that was modeled off the Gnuse.  Its in the weeds now and hasn't been used in 20 years because a skid loader or forklift are 10,000x easier and more comfortable. I recall using to haul a few pallets of landscape blocks that probably weighed 2,500 lbs.  The tractor was a CaseIH 7130 MFWD with a half rack of weights and I thought I was going to tip backward the entire time.  I also have an Ag Krane and if I'm lifting anything heavy and don't have to move I put the stands on the ground before lifting.