No experience with "custom channel", but I created a lot of spells with some CATA and MOP visual.But, I don't really understand your problem. You mean your spell is working, the visual effect work ? Or is it just the animation of your character that cause you issue ?
Let's break it down. *hammertime*Drain Soul, Life Drain, Mana Drain, Health Funnel. These are all spells that are channeled and have a channeling visual. Drain soul looks like a funnel of souls going from the target to your hands. That value to make that visualeffect appear, is in FLOAT. And to know how to get a float value to its integer form, you need to know its base and exponent. I know neither of those.
The content of the row is just the color HEX converted in decimals.