My 3-60 ACCs are 27" at 70lbs of draw weight. But I'm shooting 125 gr. Muzzy 3 blades with 3-4inch feathers. I'm also shooting off a MZE. Mine fly great, best scores with BHs I've ever shot. At 28.5" you should be able to get them flying good. Your spine should be fine. High and left tears would show weak spine for a release shooter. Least ways that what Easton says. I'd start by tuning your bow for the ACCs. Drop your nock point a little at a time and see if it clears up the high tear. If your left portion isn't too bad I'd move on to group tuning. Do some fine tuning and perhaps you won't have to buy new BHs.