You shouldn't be taking ANY grams!!!
250mg should really be the max if you want to be safe, if you can't stick to that though never go over 500mg... and that's still far too much of pure MDMA.
You can't really roll for more than 6 hours tops, you only have so much serotonin. You can keep taking MDMA, but eventually you get a shitty ass high that is closer to methamphetamine than MDMA. This is because if you keep dosing once you've used up all your serotonin from that initial release, your body starts releasing dopamine and norepinephrine instead of serotonin which causes a ton more side effects and an overall shitty high.
You can't really roll for 9 hours... but if you spend an hour or two sober, drop 150mg and then 100mg an hour to an hour and a half later at the most, you should be able to roll for the whole event if it's good MDMA.
Don't redose more than twice at a MAXIMUM, I try to only take one extra dose. The more you take and the longer you take it from the first dose, the less serotonin is released and the worse it will make you feel