Are there any structural engineer here ?

I am doing one of my invention ( Jib for forklift this time) and want find out how much weight simple steel RHS beam could carry ? Suppose that fork is 1 meter long and I extend by another meter to lift a weight, say 2 tonnes.

What could be minimum RHS ( rectangular hollow section) needed to withstand the load ? I just welded jib using 125x75mm , 3mm wall, 2 meters long. Forks are 100 cm long.

Is my RHS beam it big enough ? what max theoretically load could withstand ?