If you’re dead set on shooting 80#, cut your arrows to 29.5”. The arrow shaft will stop at the front of your riser at full draw and you will not be drawing your broadhead into the arrow shelf area. Doing this will allow you to shoot the 250 spine. A full length shaft will most likely be too weak. I honestly don’t see the point in pulling 80# for a whitetail. I pull 60# and have 26” mods on my Lift and it’ll blow through a whitetail like butter with a two blade mechanical and a 4 blade fixed. I wouldn’t hesitate to shoot that same setup at an elk, but only with the fixed head.
Great advice...thank you.