Agreed, a GT under 10kg and under should never pull drag, even on light drag settings. You should still be able to lock them on PE4, that line is still very strong, especially if matched with a softer rod. Maybe tie an extra long leader to give yourself a little bit more "spring" if a larger fish strikes.
Do the different snappers have soft lips that you could pull the hooks out of? We dont have those fish here in Hawaii, so i have no idea if locking down on them is a good idea.