Well for heavensakes..... what you really need to do is to use regular everyday common household white sugar. Yes, sugar of the cane or beet variety. Use 5/8 cup for 5 gallons and you're golden. No need to buy extra DME, and no need for corn sugar, never ever again. You've got a pound of sugar in your pantry at all times, right? Right.
I use whatever I have available, often table sugar. Since sucrose (table sugar) is a disaccharide, the yeast must produce invertase enzyme to break it down before it can be metabolized. For this reason, I use dextrose in high alcohol beers when the yeast are already stressed. FWIW, DME for priming allows a beer to be considered up to Reinheitsgebot standards.