I shoot GT traditional 35/55s, .500 spine @ 8.6 gpi, out of three longbows in 48-53# range. One is cut to center and two are +1/8". I normally use GT screw in brass weights with a std. aluminum insert, which allows for a little easier weight adjustment. My arrows are in the 29.5"-30" bop length range, and weigh out around 500-540grs.
Beman ICS bowhunter's come in .500 spine, and are good shafts, for the money imo. They only weigh 7.3 gpi, but can be front loaded to get the total weight up, giving you a decent foc as well.