if i read right your wanting Carbon arrows for a 45# bow and you draw 28 inches.

i think .500 spine is the most flexible Carbon that ive seen.....if you find a .550 or .600try them too.

get the 500 spine at full length(uncut) 32 inches?????).....and see how that works. if they are too wimpy then take off 1/2 inch at a time..

you dont want to make the mistake of getting too stif an arrow. they will be worthless then.

dont forget you can allways go aluminum you can still get older eastons on-line in about any spine.
youd probably want a 1916 in alum