If staying with the fixed power, go to the 4X model.
I opted for the VX-3 for my .460, and both my long-barreled Casull's. I like the ability to turn up the magnification at 100 and beyond. (have several on single shots too)
A middle-of-the-road expenditure would be the Bushnell Elite 2x6 - a really good and durable variable.