whenever i travel on a shaolin trip it is carry-on only, unless we are bringing a lot of stuff with us. but still, it is only a personal carry on.
first time was for 3 weeks in china, and that was only carryon, and also something you could carry with you due to the political situation we never knew if we were gonna have to fight or flight.
so that being said it really taught you how to be frugal with the clothing.
you can have your tshirts and just plan to bleach/wash in the sink every so often. no socks or underwear should leave you plenty of room as socks can take up some space, and shoes too.
basically anything bulky you want to be wearing, and rolling things up can save some space as noted, although lately I switched back to flat folding with rolled up stuff at the folds to stop things from creasing and that has worked wonders for the last couple of years.
to this day i mostly carry my stuff in a burton snowboarding back pack that expands a bit. it's an awesome piece to have so you might want to look into something like it.