I would just stick with corn sugar. The tabs always seem like a pain in the neck.
Also +1 on the table sugar no-no. Used it on my first saison, which took months to condition, then I all but wrecked it with table sugar.
Corn sugar is glucose and cane sugar is sucrose. Glucose is a monosaccharide (simplest type of sugar), and sucrose is a disaccharide (not as simple), made from a glucose molecule and a fructose molecule.
Not being a yeast expert, my opinion is that once your beer has the flavor you want, give the yeast something simple to metabolize that will result in the ONLY component you are missing: CO2 (and a little alcohol). Who knows whats in those carb tablets. Monosaccharide/glucose is where its at.