I've been using a horsehide Theis IWB to carry a full-sized steel pistol for, umm, probably a year and a half now. I, too, have to cinch my belt down pretty snug, but I've never had a problem with the Kydex shell collapsing when the gun's unholstered. I think mine squeaked at first, too. Either the squeak went away, or I quit noticing it. Not sure which.
I'm a lawyer, but I'm not your lawyer. If you need some honest-to-goodness legal advice, go buy some.