I take armor, with some added thryoxine. Armor makes a huge difference to how I feel - particularly mentally.
On just t4 my FT3 is never in range.
With t4 the lights come on, with t3 there is color!
However, if your tests show that both your FT4 and FT3 are in range, there is probably no need to use armor or cytomel, other than as a trial to see if it makes a difference.
Sally
I have Hashimoto's for 2 years now and am up to 75mcg levothyroxine. I am prone to depression and this desease isn't helping. My doc said to try the Cytomel but did say there isn't evidence that it helps. Said some people do feel better with it. I personally notice a difference in my moods when i am on Cytomel versus not. It's not a cheap medication and as far as I know, there isn't a generic for it. Good luck to you!
T4 does convert to T3 -- Armour or the addition of cytomel is a consideration, but the research on this is not that convincing - although some patients feel better with it.
Target TSH is around 1.0, but "fine tuning" between the 0.6 - 3.5 range you mention is not likely to make a difference.
So, from thyroid standpoint the options are do nothing or try some T3. Otherwise, look into non-thyroid causes or life-stressors, etc.