Those AWG scales are GARBAGE. +/- like 8mg, and they intentionally "stabilize" the reading to camoflage their unacceptable drift. By stabilize, i mean, hide the effect on the displayed weight of adding small amounts of material, as well as hiding the noise and drift of their sub-par sensor.
Any scale that isn't meant for lab use isn't suitable for anything that requires doses of less than 25 or 50mg. It's better than eyeballing, but only barely.
You can get used lab-grade scales for incredibly cheap on ebay though - i got a 0.1mg scale, that's reasonably (it reads maybe 0.3% high, and drifts an mg or two per hr) accurate for only $75 because the display is burned in and a bit hard to read. There are similar deals around for milligram scales too.
Avoid anything that's selling new for under $50, or anything that's selling new for more than $50 but looks just like all those cheapo scales.
Regarding liquid dosing: It works great, and I did it extensively before I had my good scale....
200mg 2C-I in 200 drops would be pushing it though - 30 drops = ~1ml (depends on your dropper, i have some that produce drops half that size), so that'd be ~6.67 ml - so by my numbers, that wouldn't dissolve the 2C-I. Presence of a 2C did not change the size of a drop noticeably in my experiments. Your enemy is evaporation, because that'll throw off all your measurements. Ensure that the containers are stored right-end-up, tightly sealed.
I'd do something more like 200mg 2C-I in 200ml of 20% EtOH (half vodka half water). Measure with an oral syringe, turkey injector* (take the pointy thing out and replace it with a short length of tubing, the most common aquarium tube size can be wedged in it's place and make a good seal), graduated cylinder, etc.
Always re-seal tightly, and if you are going to leave for long periods of time (like months or something), mark the level that it was at when you left, so when you come back, if the liquid level is lower, you can refill to that level and maintain the original concentration.
A few numbers. These are not _super accurate_ and were determined empirically for a saturated solution... but this should be useful as a general guide. You can't use these concentrations in practice (because you don't want it to crystalize out on a cool day), but this is a starting point.
Temp was 75 F
2C-C ~100mg/ml (!!!)
2C-B ~45mg/ml
2C-I ~25mg/ml
2C-T-2 85~90mg/ml
2C-D ~100mg/ml (!!!)
2C-E ~70mg/ml
In dH2O, 2C-I slightly under 20mg/ml
In 40% EtOH, 2C-I ~50 mg/ml
2C-I takes goddamned forever to dissolve, no matter what you're dissolving it in. Others go into solution much faster.
The point of those high concentrations was to be able to make a solution that could be dosed based on a dropper marked at 0.2ml, with one to two dropperfulls being a full dose. I eventually canned the idea because of evaporation, and the fact that I very rarely dose away from my milligram scale. I'd do it if i was going to be dosing something among a lot of people though - with 2C-C/T-2 you can get the concentration high enough that it's possible to put them under your tongue and not have trouble not-swallowing.
*Yes, they make turkey injectors. You use them to get your turkey high on seasoning+gravy while you're cooking it. They're in the cooking section of many stores and avail online. Make sure you get one marked in ml, not tablespoons. Sometimes called flavor injectors. No, i'm not kidding:
http://www.amazon.com/s/ref=nb_sb_ss_i_0_15?keywords=turkey+injector
