If you draw a true 28" you can cut arrows to 29.75 inches, use 3 four inch fletches, 145 grain point and use a 12 strand FF string and be within a tenth of being on exact spine based on Stu's Calc. There are lots of factors though that we don't know.
1) How is your form?
2) Do you have a solid and consistent release?
3) Do you draw a true 28"
4) What are you hunting/are you hunting?
5) Are you just shooting for target set-up/3D?
And a whole other list that I'm sure I'm not even thinking right now. Other than that I think you'll be real close with what I mentioned but with almost identical numbers to what saumensch already posted.
Good luck, try it out, (there's no harm in trying it out), and see what works the best for you, your shooting style and form, and what you feel will provide the best, cleanest and quickest kill for your prey should you be hunting.