^ not so sure about those figures, I'd say you could have "an overdose" (potential serotinon syndrome) on MDMA from under 0.5g. People have been hospitalised from 2 or 3 strong pills in the past after all; massive overheating, vomiting, uncontrollable muscle spasms etc etc. Not at all pleasant.
Re the vege caps from chemists, The ones I have dissolve pretty fast. You could always test one by placing something colourful in one (perhaps a tiny bit of dry watercolour paint would be perfect) then drop it in a glass of water and time how long it takes for the colour to seep out? Also take into consideration that the low pH of your stomach will make them dissolve faster again.