Interested in adding a red dot optic to my SAO 226 Sig legion.

Never used one on a pistol and don’t know much about the process outside of buying an optics ready model.

Is this a complicated extensive lengthy process? Or fairly simple?

I don’t need new higher sights, just want to have it milled, and have the option to have a plate to fill the mill slot if not using an optic down the road.

Is there a universal cut for many optic options or do you need to choose an optic specific cut.

Any site sponsors that do this work, or anyone else you could recommend?

The milling is easy for the pros, but a cover plate to cover it back up if you don't like it will be the sticking point.