It's going to depend a lot on what sort of answers I get, but I will lay my cards out now and say that Gil would be willing to deal under the table in terms of saving Leathann. And he would be willing to deal substantially, because he's stubborn, he just settled down there, and he's going to see the Void as an affront to his rightful kingship among other silly Gil things. He knows Rin has talent as a magus and is willing to take a considerable ding to his pride if it means getting what he wants.

So ideally, he'd pull her aside in privacy and make an offer of sorts to this effect. He's pretty serious about this and would shoulder the responsibility if worse came to worse re: discovery of them working together.