[...],
I know each person is different and it's not a contest to see who can manage lack of sleep better, but at 6 months off, my sleep was still pretty bad and I had at least 5 - 8 zero nights per month. So it's not uncommon to still have a zero night here and there and then think that you're not making any progress, but that's not true. Healing from Benzos doesn't occur in a linear fashion like healing from a broken bone or a nasty cut. It's up and down and all over the map.
Give the Seroquel a shot, but 200mg seems like a lot to start with. I'd start lower and then you can always increase the dose. Seroquel is an anti-psychotic and it worked OK for me most of the time but at somewhere between 50 and 100mg per night. I took Seroquel on and off early on in my WD, but then decided to ditch all Rx drugs for sleep, but you do what is best for you.
I would never reinstate Benzos....that is a dead end road...even if they worked again, you'd have to keep increasing the dose to get the same effect and that is like taking rat poison IMO.
I normally would not promote Rx drugs for sleep, but I'd choose Seroquel over any Benzo 100% of the time.
Good luck.