I'll make the assumption that you are drawing 28" and will cut your arrows to 29" BOP, with a 125 gr point. BW's are cut well past center and this makes them like a heavy spined shaft, so I would recommend 70-74, more if you want to shoot a heavier point. For a 500 gr arrow I would recommend the Sitka Spruce as well. A 2216 will static spine about 84 lb, but it's not unusual for aluminum to require a higher static spine than wood to shoot well. How long are your 2216's and how do they shoot for you? Have you bareshafted or paper tuned them?
A set of test arrows with a variety of spines will help get you tuned quickly.