How much do you think a planet weighs? The moon alone weighs something like many billions of tons. You realize the problem in talking about a mere 600 tons? Not 600 million or even 600 thousand, but 600?
Just for reference you know Galatea from the Justice League cartoon? The adult clone of Supergirl? You know she casually holds 2000 tons with one hand? This is important because Kryptonians in the DC animated universe don't even come close to their post crisis comic counterparts who in turn don't even come close to their pre crisis counterparts. Post Crisis Pre NU Superman can handle billions of tons on his own. So you again see the problem with the figures you mention?