Sleep and related issues

Question 1- have noticed that since I reduced my Lithium from 1000 to 800, there is no noticeable difference in my sleep. Any Lithium takers notice any changes in sleep patterns? ( I'm also on Remeron/ Mirtazipine) maybe that's why my sleep is OK for now.

Question 2 (non- sleep related)I'm currently hoping to taper down, probably over many months, my Lithium , due to side effects. The main side effect is that I have lost my fun/emotional/ spontaneous side. It can only be described as feeling emotionally dull.
Does a lower dose of Lithium usually mean less side effects? Seems a silly question, but I'm hoping that I can get off it safely and wondering what I should look out for during my safe, supervised taper.