Why? I mean what is your goal? Usually both eyes open is for speed shooting, fast transitions between multiple targets, or moving targets (like shotgun games) Are you talking about pistol or rifle or what? I'm not a fan of the term "point shooting" because it implies there is no aiming involved. There are different levels of aiming. Think of it like different quality of sight pictures, you'll need to buy a lesson for more on that
You see double because its not possible to see near (sights) and far (target) in clear focus at the same time.
With a dot sight It is more natural to focus on the target, and thats exactly what you are supposed to do with one. A target focus with both eyes open, looking through the glass with the dot appearing on the target is easier for your eyes and brain to line up compared to rear aight, front sight and target alignment.
I would love to get into speed shooting in the near future. I have read a lot about the benefits of shooting with both eyes open both in defensive and target type shooting with a pistol. I have heard of guys that have shot for years having trouble transitioning to shooting with both eyes open, so where I am just starting, maybe I should just jump right into it and learn it now. Maybe I used the wrong term by saying point shooting.