I agree with Big Jim, although I couldn’t see myself ever using .600 spine arrows with your setup. Don’t be too quick to cut the arrows; you might want them considerably longer than your draw length to fly well. To reinforce, Gold Tip .500 spine arrows used to be called 35-55, meaning they were spined to be used with bows from 35-55 pounds, so you would be right in the middle of that range.
Now, it is possible with some EFOC weight up front, considerable more than 200 grains, a .400 spine shaft could be appropriate, particularly if a person were drawing more than 28”, but in your case, which is close to my case, I would say .500.