i swear, saul, that many of my truely significant ideology shifts have occured whist stoned. in addition, i have written stuff down, and checked it in the morning, to find that it holds insight, that i had forgotten but that proves significant even when not under the influence.
in short: don't think you can write war and peace in one session. don't even think you can really achieve anything. but think, explore the mindspace, and /write it down/. then analyse and evaluate in the morn/next day, and THEN create.