I would guess those arrows are extremely stiff. If you want a cheaper arrow with some weight to it try some 2018 aluminums. They are tough for aluminums and have nice weight to them.30 inch center shot 400s are stiff out of my 55 pound recurve with 225 grains on the front, and they are 30 inches long. A 400 centershot cut to 27.5 inches is a very very stiff arrow. Aluminums are nice, you can cut them yourself easily and they are cheap. A 2018 cut to 30 inches with a 125 point weighs around 540 grains. Don't be afraid to leave your arrows a little longer. Bareshaft tune and see what length you end up with. I am also assuming your draw length is less than 28 inches. Don't rule out 500s if you stick with carbons. Remember carbons get stiff very fast as you cut them. Start full length with whatever shaft you choose and let the results dictate what length arrow you end up with. If you intend to hunt, I would shoot for a finished arrow weight of 9 to10 grains per pound, 55lbs = 550 grain arrows. It's not a set rule, but most of my bows shoot even sweeter with arrows in that weight range and pass through deer easily. Good luck and enjoy, nothing like shooting a stick bow.
Matt