Yeah I used to take 3mg, or 3.5mg, but over time and literally hundreds of lifetime DOC trips, I have settled on 2mg as my usual dose, it's quite strong enough. I am usually trying to go hiking or something on it, I would still take 3mg but it's a little heavy for that.
Yes, anything over 3mg requires a safe spot to retreat to after a few hours. During the come up it's good to keep moving around and explore, but I find that after 3 hours I may need the comfort of my bed!