the reason why there's no set answer is because not everyone needs extra choline. some people don't get the piracetam-headaches that others do when taken without choline. i, for one, did get the headaches, and did supplement a bit of choline. for me, however, i preferred to use a simpler source: lecithin. Recently, i've ordered some CDP choline, and plan on just keeping it to a low dose: 250mg a day, once every day or two, and thinking about starting piracetam again.
when i was using piracetam, about 8:1 was my "headache threshold" but more often than not, i used a 4:1 pracetam-to-choline ratio.
simply put, don't bother with the extra choline if you're not getting brain-fog or headaches.
edit: however, if you DO decide to use choline, Centrophenoxine was my favorite!
Edited by Pike, 19 August 2009 - 07:39 AM.