Oh sorry to see that after nice flight and especially after the auto land showing you going to get it,hopefully damage not to extreme and can be fixed,,have to ask what are nats? Pesky birds....looks like you might get away with just clipping shell back togetherTook my backup bird out to stretch its legs and end up with a damaged unit
Torx T6 is the size you need. I picked up a little cell phone repair kit at Lowes and I just keep it in my backpack with the Phantom.
The kit I bought has all the small Torx and Phillips sizes and a few others like security hex (for the ones on other devices with the pin in the middle to keep a normal hex wrench out) as bits that fit into a precision screwdriver handle, and it has the plastic pry bar that is handy for undoing the snap locks around the edge of the body.