when you pre-melt the spice onto the stone, don't just "give it a blast"; you risk burning your dose before you even get it into the GVG (or whatever pipe/device you are using)
place the stone on a glass surface and heat, from a distance, from UNDER the stone...this warms the stone gradually and you can see the spice slowly melt into the stone. this works perfectly.
a side note: this past weekend, i found a stone that had been pre-loaded almost 4 months ago. it had been kept air-tight and dark. no loss of potency whatsoever.
this is a good tip for "goo"....just dab goo onto stones and store away. no need to try to put it into a container. if you reX - that's another thing, but keep the stones full of goo for a later journey