Seachem used to label its bottles with the amount for 1g doses and include a drop cap. I'm sure someone figured out it made for better profits if folks found it difficult to dispense small amounts and thus used more product than needed and changed their labels and caps to encourage the overuse. It's not toxic until you way overdose, so the customer buys more often.
Happily, I still have one of the tiny old bottles around. Rather than haul out the big bottle every time, I refill the small one (with the drop cap) and keep it out of the way on the frig next to the sink. Measurement for 1g is 2 drops.
If you can't find a drop cap that fits your bottle, you can use an eye dropper. If you're worried about the size of the drops, you can just use 3 to be sure, but I've measured with the drop cap, a pipette and an infant's ear/nose bulb and found the drops to be close enough in size to not matter. For that matter, there's a time or two I've dropped the cap in the sink and just done drops off my fingertip.
VERY convenient for filling gallon jugs--line 'em up, add two drop, fill with water.