Short answer is "it depends". I like a few different options, in no particular order:
1. Have the receiver drilled/tapped and slap a CROM on there with an Aimpoint. This is probably the easiest option, as it's a standard pattern that most any competent smith/shop ought to be able to do.
2. Have a Vang barrel optic mount installed. This keeps the top of the receiver clear for emergency reloads and helps with return to zero if you take off the barrel for whatever reason (cleaning, etc).
Most anything involving a pic rail will result in an optic mounted too high and you'll need a riser on the stock, which I tend to dislike because it just doesn't seem to mount as intuitively, especially at speed. YMMV, of course. And I agree with Dan, those sights are pretty low so I'm not sure a CROM would cowitness. But it'll certainly be more likely than anything with a pic rail interface