I'm also a "Burris only"believer. However I have only used them on a 7 X 30 Waters Contender, and a .44 mag Anaconda, so I am not speaking from experience when it comes to the .454. However, if I were scoping a .454, I would try the Burris signature rings and the pos-align inserts. These rings allow you to zero your scope without using the scopes internal adjustment. According to the Burris advertisements, this allows the scope to perform at its best. This seems to make good sense to me, and my scopes sure seem nice and clear even in low light situations. The one thing I know for sure, is that it sure makes zeroing the scope a snap. Also, based on my .44 mag experience, the nylon inserts seem to hold the scope quite well. Much better than steel rings, even those that have been lapped.
By the way, you might want to consider the Burris 2 X 7 scope in place of the Leupold. I can't say enough about my Burris 3 X 12, and you'll keep about a hundred and fifty bucks in your pocket.