300mG is too much for a second time. You will very quickly lose the magic of MDMA if you take doses like this.
Faced with your dilemma I would do 70mG + 40mG + 40mG over the time of the rave. Space it out as required as you feel.
Try and limit the dose to 150mG if you can.
If you want a more intense initial hit 100mG + 25mG + 25mG.
Personally I would prefer to remain steadily fucked over the rave rather than very fucked initially then less so towards the end.