It was on his arms and legs, not benching, which means it's about 7~10 times more.
No clue what trying to do high speed punches and kicks adds on. Probably about 5 times, since 2 tons on each limb he could do w/ punches and kicks but he was having trouble with holding the 10 tons on each limb.
2 x 10 x 5 = 100 tons
40 x 10 x 5 = 2000 tons
Base Goku's max weight is somewhere between 100 tons and 2000 tons. Dragonball feats and increases in power would suggest its on the higher end of that range.
SSJ Goku had no trouble whatsoever with the 10 tons on each of his limbs. 'd say even less trouble than he had in his base form with 2 tons on each limb. Using that comparison, I'd say that he could sustain another 5 times increase in the training weights. So, SSJ Goku's weight capacity is at least 10,000 tons.
It's really hard to say what SSJ2/USSJ and SSJ3 would do. I think that SSJ2 could lift at least 50k tons and SSJ3 could lift at least 250ktons would be reasonable, but it's requires abit of speculation at this point, even to get a low number.
Furthermore it was stated in a databook that using flight made the training much harder, therefore this is a low end of Goku's strength.