This is a very simple AddOn that allows you to set the font size of Blizzard's Scrolling Combat Text.
Please note that this AddOn does not modify the size of the damage numbers that see in the world above targets that YOU damage. AddOns cannot change the size of these numbers.
Just use Grayhoofs SCT. Blizzard totally ripped it from him, and they did it bad also.
Theres way more SCT can do, and no, it almost doesn't use more memory.