Thanks for the replies all. Skull has decided that the easiest thing to do for now is to leave things as is, and then in perhaps 2 months or so down the road, he will evaporate 1L of this solution to pure dryness and see if there has been any considerable loss. He may repeat this experiment again several times over the course of many months if the results are satisfying enough the first time around. But if they're not, he will try this whole thing again using tartaric acid rather than fumaric for salting DMT and let you all know how it goes.
Also, an mg scale just isn't the skull's budget. He's not prepared to toy around with the cheap ebay ones after his bad experience with them, and he doesn't have the spare cash for a decent one. No matter though, his DMT fumarate solution has been serving him very reliably as of late, and if he sees a deterioration in that trend, he will simply do what it takes to overcome. He's confident that this method can be made to serve him well.. well, he really wants to believe it anyway..
EDIT: in fact, the skull just realized that he actually has roughly 2g or so of DMT fumarate dissolved in a small amount of water from over a month back. He will evaporate this solution at the time of his next convenience and see what he is left with.
I am awake in a dream called reality.