As far as your question about optics, I just made the jump to open myself and have found that the cmore slide ride has been amazing.
I have a shorty and the dot tracks very well for me, I like the big glass for seeing a lot. If you go the slide ride route I’d recommend the aluminum click version. I’ve played with both and the aluminum click is superior to the plastic non-click.
To be fair I don’t have too much experience with the other optics common in open but I’ve been happy so far.