Does anybody have any idea what size torx screws are used on a typical enclosed trailer to hold the skin on? This is a US Cargo brand trailer.

I have a T15 and a T20 bit, but the T15 is too small and the T20 is a hair too big. Is there another size in between or a metric size? (Really doubtful on the metric thing.)

I would ask the dealer, but they are closed until Monday and I really wanted to get this taken apart before then.