Just guessing here, but the bow has a cut-in arrow shelf, right? If so, being center shot the bow will probably not be too very picky about arrow shaft spine weight. As long as the spine weight of the arrow shaft is close to your bow weight they should fly fairly straight.
What are you looking to accomplish with the arrows? Do you just want arrows to throw at a target or are you wanting to challenge yourself with crafting arrows that could have came from a Lakota warrior's quiver? Or maybe you are in the Society for Creative Anachronism and your personna is a samurai so they have to be cane arrows shafts?