TL;DR I suggest the TCA trimipramine as the psych drug for insomnia. Random rambling about how I'd handle sleep with a pretend patient.
Do not use quietipine; sure, it'll knock you out but it has a greater side effect profile than the ones you mentioned. (yes, I realize that D2 is not occupied by this dose)
If trazodone works for then it's definitely the best option of the three; if not, I bet mirtazapine will do something for you, but it does have bad off weight and appetite effects that are more troublesome than those associated with trazodone. Mirtazapine is a good drug and it may have some good antidepressant properties (much superior than trazodone) if that is what you're looking for. Also, it causes some really fantastic dreams! Notorious for this.
Honestly the best TCA for insomnia, in my opinion, is trimipramine. More sedating than trazodone and seems to cause, subjectively, less of a hangover effect.
I suppose a psych will want to use psych drugs to solve every problem, but if you're looking for nonaddictive things to help --> try tizanidine; nonscheduled and very underrated..
I'd try out a tizanidine first; if this works, you won't have to deal with a next day hangover like you might with these drugs.
For a patient with sleep problems, I do it like this:
First Line: tizanidine 5mg. po qhs #30/hydroxyzine 25mg. po qhs #60 /gabapentin 400mg. po qhs #30
Second Line: trimipramine 25mg. po qhs #30/ flurazepam 15mg po qhs prn #15
No sense in giving out more bullshit if ^^^ doesn't work.
Third Line: quazepam 7.5 1-2 tab po qhs #60
Time for z-drug? No way! quazepam is far superior (and still GABAa specific) It is underprescribed and superior to zolpidem; it improves sleep architecture, and drug tolerance is not as swift
I'd be hesitant to write these z-drugs. Too "wild". I'd move on to triazolam and tempazepam.
Quazepam (Doral) :
http://en.wikipedia.org/wiki/Quazepam
I think the best fourth line drug would be zolpidem followed by triazolam (Halcion).
At month 6, if you still can't sleep; I think it's time for Seconal followed by chloral hydrate followed by Xyrem (GHB)
lol, if you went to me; by the 8th month you'd be on Xyrem.