I personally prefer a straight 2X or 2-1/2X on large bore kickers. The scope should be mounted ahead far enough to cause you to reach. Then - practise mounting and snap shooting at close targets. A straight 2X gives plenty of magnification for large game out to normal ranges. Mounted like this, the view is always wide open, sharp and clear on the Leupold 2X. As well, it never comes even remotely close to the 'brow'.
: I firmly believe a variable shouldn't be higher than 4X or 5X.
: If you get a variable, check it for accuracy at ALL power settings. I had a couple Redfields and one Leuy that weren't consistant in bullet impacts through the power range, so switched to fixed power for .375 and above. The .375 has no difficulty keeping in less than an inch with the 2X at 100yds off the bags, yet offhand, the 8 inch plate at 220yards is a generally 3 out of 4 proposition.
: Practise!