I don`t know shit about this but it sounded like a challenge. Looks like you can`t use weight precisely but i guess you could use it for estimates. im guessing temperature plays a role on some materials.
I also suck at chemistry and stuff but i know the electrons jumps with the speed of light and that there is some time delay before the other electron jumps further (speed of light)
I also think its related to the amount of electrons in the outer shell of the atoms if its full it will lead better i think. or become a unstable isotope. Just guessing.
Magnetic abilities in steel is related to the structure in the steel so if we look at stainless steel we will also se that it does conducts heat better than ordinary steel.
We have a pattern now..
Copper leads heat briliantly and so does aluminum. that i know.
Gold, silver, copper and aluminum does all corrodate poorly or not at all.
By mixing materials and observing their heat conductivity and corrosion rate you could perhaps get some indicators. and blablabla.
happy with your answer?