Good timing, I just started DEC myself (400mg/day). I am around 77 kg.
I also have tried just about every parasite drug you can name, but I feel that DEC was able to 'hammer them' much harder than any of the others. It may have helped that I also coincidentally began taking large doses of astragalus root at the same time (4-5g/day) which gave my immune system a turbo boost. That herb is amazing.
As for what my parasite issue is: I have no idea, but I suspect it is some sort of threadworm or strongyloides from my time in China, or else visceral larva migrans (caused by the dog hookworm; I own dogs and did not properly worm them for years as well as live next to a dog-doo infested park). At my worst I had serious pain in my neck lymph nodes as well as excruciatingly painful leg swelling/edema. Also my spleen felt like it was going to explode.
The first two doses of DEC gave me major die off, stomach upset, and crazy dreams (I was doing battle with wild animals trying to kill me).
I was taking fenbendazole before I tried the DEC, and it was helping but only mildly.
I am going to up my DEC to 500mg/day in line with you guys.