Hi,
Personally, I would shoot the most accurate slug of the bunch, and not care about velocity or energy. Shot placement and not paper ballistics is what kills. Any shotgun slug within it's effective range will work, more than enough energy to take a deer.
Now about that 150yd shot, don't even think about it. You're talking about a shot is about at the limit of a .30-30 leveraction! Maybe with a Tar-Hunt boltaction target shotgun locked down on a solid bench, you might be all right after a lot of practice. But your Bennelli, (as good a gun as it is), ain't meant to take those kinds of shots. Keep your shots to under 120yds. And the closer the better! I'm far more impressed by a hunter that can get a 20yd shot over one who has to take a 100yd shot. We as hunters owe it to our prey. One shot - a clean kill.
Dale