idk... even with the grabs...
2 should be enough, i mean, rly.. by the time u draw ur silurian dragon (the one that uses the most time quanta), u should have stacked up a whole lot, nor do u need that dragon anyway... as the shriekers will be the most dmg output
think about it like a shrieker rush, just one time mark is enough to evolve all the grabs, and that's rly what the time quanta is for, the dragon is just an addition to the FG, cuz it has triple mark, so there is a lot of excess time quanta