a good rule of thumb i use for
table salt: morton's: diamond crystal
1:2:4

1/4cup table salt = 1/2cup Morton's kosher
1/2cup Morton's kosher= 1cup Diamond Crystal brand kosher

or you could use a scale for extra precision, but i don't own one. i cook with diamond crystal, which is obviously coarser than mortons (and doesn't have the anti-caking agent like mortons) and often times i'll follow the recipe w/o the salt volume adjustment and it still turns out fine. as for sea salt, i don't think it's possible to give an accurate equivalency since it varies in taste depending on producer. feel free to correct me if i'm wrong, but that's what a chef once told me. and since sea salt is a finishing salt, just go by taste. goodluck in your search.