Tried it at all kinds of doses, from 200 to 1,200, my sticking point was right around the 600-800 mark...never noticed much of a difference with anything higher than 600, but at the same time, on the low side, even early on in usage, I didn't get much out of it unless it was at least 4/500 (always stacked with at least test of course)...like yardrock said, around a gram, and more importantly, like xcel said, depends on where you are now, and where you have worked yourself up to...
So, with all that, how much have you used before, have you used it before, and if so, what were your results with it, then adjust and go from there
If not at all, then I say go with the fellas, and give 400-600 a shot and see how that works for ya