I take 400mg seroquel...200mg at night and 200 mg in am. Serquel does level me out, but also seems to keep me mildly depressed. I sometimes thinkk I get depressed and not a necessarily like a bipolar depressed....just a disinterested,blah feeling. I do not think if I remember correctly been manic on seroquel. It was initially given to me for psychotic stuff going on and seroquel is the least likely to cause tardis dyskenesa (which I have mild TD from some of the other anti-psychotics). If 300mg keeps you from being manic then guess in interest of your dwinding check book, i personally would opt for the 300mg or discuss with doc, but maybe 250mg would work for you.
I have always liked the "happy" of hypomania or mania, but have also experienced the financial ruin it can cause. I do know I have had deoressions unrelated to BP, but they are usually short lived and can be tied into something that is happening at that moment (fight w/hubby), sick horse, financial distress. etc. Once those issues have been addressed my depression definitely gets better. But I do think BP people REACT to some of these everyday issues with depression rather than simply dealing with it. I just wish there was some magic pill combo that kept me "happy" and I did not experience all the insane mood swings