Maybe he doesn't have a scale at all. If that's the case though I'd advise caution - liquid measurement is only accurate when you know the initial amount you're working with. If you're expecting 1g and your vendor decides to be nice and send you 1.4g, you go to dose 10% of your solution hoping for a 100mg dose and end up with 140mg.
If ever dealing with liquid measurement and only a rough total dosage is known, then the best is to then titrate from a fraction of an expected dose of solution upwards until you find the right dose; this amount of solution will then be a good dose for you again in future so you can dose accurately. The downside is that you don't know exactly how many mg this is, but this is the safest way to measure if you don't have a scale and only known a rough total weight within a certain degree of accuracy. You can't titrate when eyeballing since piles will not be the same each time, but a given amount of solution (provided none has evaporated) will contain the same amount of substance - allowing for titration.
Anyway iirc it's water soluble but don't quote me on that, maybe someone else can confirm and if so how soluble.
Regarding dosage, I found 111mg similarly potent to 40mg of 2C-B when I tried it as I think I already said, and since people don't really go much higher than that with 2C-B, maybe occasionally to 50-60mg, I think you can definitely get the full experience with this too.
This one seems more adrenergic so I think maybe this should be treated more like DOx compounds with increased dosage, and in terms of toxicity, i.e. don't just take 2x as much for a crazy experience like you might with a 2C-x as at the very least it's likely to be overstimulating, and we can't yet be sure how safe it'd be.