Frank,
The miniblaster's blades are 1 3/4, as are the miniblaster 3L (that designates a flare or outturn on the ends of the blade. Rocket says "large extended tips for quick opening at lower speeds."
There's also a miniblaster 3XL (extra-long tips), plus the blades for the Sidewinder are 1 3/4" as well.
Of course, since you'll be buying a Bowtech, you could look at using Rocket's Sledgehammer, featuring 150 grains of a full 3 1/2" cutting diameter "made in response to demand from customers shooting 80+ pounds who were slicing through whitetails and still looking for their arrows!" <img src=icon_smile_big.gif border=0 align=middle><img src=icon_smile_big.gif border=0 align=middle><img src=icon_smile_big.gif border=0 align=middle>