I would start it out at a minimum of 8". 2 to 3" is way too close IMO for any ATI setup. You will fry corals with it being that close.
Get the dimmable version and you can keep it closer to the tank if you want. That way you can dial it down to like 60% or so and not fry your stuff.
Roger that. Appreciate it. I'll probably just put the work in to make some room above the tank so I've got the space to move it up and down a bit.