I have 500mg sitting here... The long duration and the crapshoot as to whether it will work or not has kind of put me off of it. I'm interested in seeing some new experiences with it. Total duration seems to be 12-16 hours not 10.
Don't drink any water at all beforehand, I'd pop an aspirin or 2 beforehand to acidify your stomach, wash down with OJ or something else equally acidic. seems to like acidic conditions.