That’s not really a stagger and that’s why the 1200 felt better because it all hit at once and felt better. You stretched out 900mg into 3.5 hours and added in 900 more three hours later. Technically that’s not staggering. If you had staggered the 1200 300mg every 30 minutes it would have felt so much better than all at once.

Gabapentin’s bioavailability goes down the more you take because it’s mode of transport gets saturated. Staggering 300mg every 30 minutes with some added fats and protein (which also increases bioavailability) is the way to go. You’ll feel your first couple of doses at the two hour mark and it will build from there.

The way you are doing it, by spreading out the amounts so far, they never all come together at once.