Modifying side gate

[richfzs]

no epxerience, but that first one you posted looks ok. Bear in mind though, that if the gate is thin like you say, there isn't much for the screws to bite into (before they're poking out the other side), so you want an option that uses a few screws, and it will still likely be easy to kick the gate open anyway (and rip the screws out), so an expensive lock aint worth it.