Well the plan at present is to ship the big order to me, and I will package and ship everything out myself; adjusting the price a bit to account for shipping/packing supplies and my time. My goal is to not raise the price beyond $200/kg (currently at $180/kg). This should be pretty easy to achieve.
As for the liabilitiy of shipping, I guess the best I can do is offer USPS insurance and to make completely sure that this chemical is indeed legal to ship to wherever it's heading. Beyond that, we can't plan for anything outside of that. In the case of the aforementioned E6 guy; that was a mistake on the post office's fault, a freak occurrence if you will.
I ship things all the time and have yet to have any serious problems; including international. The fact that it's a chemical does change things a bit, but we have to assume that the usual channels will function as their supposed to.