If you've never done Seroquel before 25 mg. is PLENTY. It's quite strong although one develops a tolerance to it quite rapidly. I was on Seroquel for about a year for insomnia and went from 25 mg a night to 400 mg a night over the course of the year.
When coming off stimulants I personally prefer benzos (klonopin is my favorite). Benzos calm me down, reduce cravings, help me sleep, and help me wake up in a decent mood. Seroquel knocks me the fuck out, then I wake up in a terrible mood and find it incredibly hard to drag myself out of bed.
I'd def say stick with the benzos.