Are you bare shafting? How does it fly? Maybe you are too weak from the start and just getting weaker as you add weight. Could need to do some cutting.
I am not familiar with that shaft or you bow center cut. Assuming a 340 shaft and ¼” out from center, I would think you could get that to work with some point weight as far as spine goes. However, I find that I get tune issues with a lot of extra shaft overhang and HFOC. Some people get them to tune fine, but I don't. 200-300 gr point weight with a 5” plus overhang cause the shaft to whip around too much for me I think.
I am not sure what the GPI on that shaft is, but I would think it is kind of a light arrow for you with only 225 point weight. A CE 250 could be a good arrow for you for spine, shaft weight, and final arrow weight. Could get you an arrow down more in the 28-29” range with 275 gr. up from and around 10 gpp.