In my opinion, think of yourself as a limbo dancer and see how low you can go hehe, there are no rules im afraid, the best way it seems is to test your bloods before and after eating the carbs and when it has an undesired effect on your bg dont eat that or at least reduce it therefore cutting down on that cabr and so on, i have found (not through trial and error, i read it so i tried it) that 30 grams a day seems to suit my eating and my bgs and everything for that matter but i know some people get by just fine on 30-40, 40-50, 50-100 and 100-150 which is very unhelpful sorry, but if i were you, id start at 30g and see how high you can go before your bgs rise too much for your liking, but thats just me im sure others will think differently good luck!