The whole brewing process takes too long and requies too much energy. I was thinking of brewing a bunch of doses at once and storing them for later consumption. I'm not sure what the drawbacks of doing that are though. Does it go bad? Do I need to keep it in the fridge? Is the potency of the tea roughly uniform throughout the liquid (allowing me to split the doses by volume)? Does it remain uniform or do the harmalas settle as sediment? Can it be stored in regular plastic bottles? Anything I should know about before trying this?

It's not a long process, only takes a few days. I tend to only brew 200-300g at a time, because it's so potent gram for gram.

Just concentrate it enough, put it in the fridge and it won't go bad. 10ml per 3g is a good enough concentration. Then shake before pouring. Plastic bottles are ok.