Oral use - Dry san pedro flour for a mescaline naïve

[BlueNarwhal]

SWIM went to Peru and bought 2 doses of dry san pedro flour. The seller told him that it was the standard amount (it was already packed in transparent plastic bags). He weighted it and found out each bag has 25g of dry san pedro flour.

He is very aware of the mescaline effects, has done a lot of research, and is very interested in the chemical and psychological effects of this amazing phenethylamine. He weights around 55kg (121lb) and is aiming for a common dosage (200..300mg for an average-sized adult, according to Erowid). He is now wondering wether he should:

1. Take the full 25g dose and leave the remaining 25g for the next time.
2. Take 2/3 of 25g (16.7g) and leave two other 2/3 for the next times.
3. Take 2/3 of 25g (16.7g) and then take the other 1/3 (8.3g) if it doesn't produce the desired effect.
4. Take more than one dose, if you think that 25g is insufficient for a single trip, and make it the only trip with this batch because there would be very little flour remaining. He prefers not to do this option because it'd be more than what was sold as the average dose, but still wants to hear your opinion.

Please, tell me which one of the 4 cases described above you think is the best and why, so that I can tell him.