well the probe itself with integrated lander is only 4 tons, now you can deduce how much fuel it has, also you given me an idea, i'll make a version of Delta IV
also the problem is that i don't have enough fuel for even go out of the atmosfere
well, the thing is that i wan't to send two joint probes, one of them will be orbiting for ever jool (until it crashes on any moon or deorbited by moon sois for crash into jool, or it looses on deep space) and a lander for laythe that is designed to be floating, the two probes has a wheight of 4 tons, both have scientific things and both have batteries, the lander have solar pannels while the probe itself have a nuclear reactor (stock) when the probes arrives to jool i'll setup an encounter with laythe, moving to make it a crash, then the lander extends its solar pannels and then the probe adjust the orbit for pass near laythe making it easier for jool aerobraking then in apoapsis the periapsis will be in betwen laythe and jool, then at periapsis adjust apoapsis near pol, the the interplanetary stage separates and at apoapsis the stage will reduce periapsis to make a crash with jool, then the probes start to extract science