I would not drill and tap a Maxus. The maxus that is factory d/t'd has bushings embedded in the top of the receiver. They have them there for a reason. I tried the fastfire mount on my maxus and it seemed like the perfect solution.
But...it would not hold zero. I tried everything that the Burris rep who used to be here recommended and nothing worked. I eventually gave up and just used the front bead. Because of the design of the rib it is difficult to find aftermarket adjustable sights that work and attach properly also.
As much as I ike the gun, it is now my waterfowl only gun.