"Not strong enough" at default treatment time, yes, but it's another one of those experience things --- because as you go on to say, it is strong enough with sufficient treatment time. Personally, I treat my water overnight when I can, and assess the water source when I cannot; if it's suspect, then indeed increase treatment time and possibly dosage.

For my trip this coming year I expect to run into a few sketchy water sources, and so plan to carry a very light inline filter to augment my default aqua mira liquid treatment (filter then chemically treat). The right approach varies, I think, based on anticipated conditions.

Ditto the trade-off in weight of using a filter vs. chemicals, it depends very much on how close or spaced out your water sources are. Sounds like where you are, water sources are pretty close together. A number of other factors also adjust the calculation, including whether you tend to drink more or less than the average, how hot and dry the ambient conditions (which impact how much you drink), and how difficult the terrain/slope is (ditto). My point here is that the weight-optimal solution isn't a one-size-fits-all kind of thing.

FWIW, you might consider weighing your water filter when put away wet --- 5.5 oz dry is fine when first starting your trip, but after that it will weigh a bit more (obviously not the dominant factor however ...).