While I like the idea of the J-hooks (that go behind the belt), I'd be sure to have a regular set of clips on hand. I've never used J-hooks, but it looks like that would put the weight of the gun on the pants, not the belt. Obviously, using any clips behind the belt (or without a belt) will run into the same problem. Maybe that's OK with a J-frame revolver, or even a Glock 36 (I don't have one, so I can't say), but I would not want to do it with a full-sized steel pistol. I'd rather have the weight on the belt. Even with something smaller, like the aforementioned J-frame, I'd be leery of using the clips on the pants only. I'm not sure they're tight enough to keep the holster in place in the event that you needed to draw.
I'm a lawyer, but I'm not your lawyer. If you need some honest-to-goodness legal advice, go buy some.