Don't quote me on this. This is me talking outta my ass but it might be close to being accurate. Also keep in mind, that i've only ever done E. one time and that was last night. So im still chatty from my effects.
There are multiple variables to consider. Weight, Mood, Thoughts, Dosage, Tolerance, And random things you might be doing through out the day that could possibly "boost" your effects (ex: Hanging out with ur crush could do the trick)
Lets say you weight 150lbs, you haven't done it in half a year which is good. I'm not quite sure if your tolerance is at a 0% or if theres still some left. But lets go on ahead and say since its been half a year ur on a nice clean slate. A full 0% tolerance level. You could easily say. Take 150mg For that nice feeling. But this is where those factors come into play. You have to be in a positive state of mind. Don't expect to roll hard and don't wish your roll was harder than what it is. When you're rolling don't be like oh man... i wish it was just a little bit more. accept what you have now and embrace it. So spend time with your favorite people and be happy that you're with them, and no lingering thoughts in the back of ur mind thinking about how u wish u were trippin harder. This can definitely reduce your roll.
So plan ahead. Are you going to be with ur best friends, ok friends, girlfriend? Pick the best you can do and be happy that you have that. if you're going to be alone find your favorite thing to do and do it! make the night/day about you! If you want to be alone thats cool too. But if you get a thought about say, going outside and riding ur bike (lol) don't limit yourself. Go for it! This is really all about ur current state of mind. That being said, How much do YOU think you need for a proper dosage. YOU know YOUR body more than all of us here, and no one here can properly tell you how much you should take. If you feel like 150 is going to be in the ball park. do it. But dont take 150, and save an extra 50 on the side for later because then thats going to be in the back of ur mind all night and all you're going to be thinking about is intensifying ur trip. Make the trip fun. Its not about getting high, remember that.
Ok now im done talking outta my ass. Like i said i only ever took it for the first time in my life last night. and thats my theory behind it. I hope it helps. Bye bye~ take care.
Update:
And idk if this helps but, as for me i took 1 pill which had probably a max of 100 in it. I'm a profound tripper, and im use to rolling extremely hard. (just believe me) I went into this with a very positive state of mind. and i was just happy that i was going to be doing it with my friends and spending the day with them. I didnt let the fact that oh i only took 1 pill, and on all other substances it would probably be equivalent to like 5 pills bother me. That never even crossed my mind. I lived it up! and had possibly one of the greatest nights of my life last night just with my buds. So yeah.... just be happy dude!