Unless they've updated their process in the last couple years (which is certainly possible), CGW would not be my first milling choice for an open emitter optic. The work they did on one of my guns did not include the alignment bosses, which are important IMO.
CGW remains my preference for other CZ upgrades.
Vulcan Machine Works in Plano, TX has done a couple of CZ P-07/09s for me. I'm happy with their work. I would also trust the other companies that Lon mentioned above.