I created a new spell. I want it to be Master level, but while I have Casting Perk set to DestructionMaster 100, the spell still is at Adept level in game. I did make it by duplicating an Adept level spell. Can anyone help me understand why that is and help me fix it?

Try changing the skill level in the magic effect to 100 (duplicate the magic effect and change that so it doesn't affect the adept spell).

I see the spell effect is set to Novice when I go to edit the Fireball:Health effect, but no way to change it. Is that what you're talking about or am I confused?

Spells are made up of magic effects, which define what it actually does. Go to the "Magic Effect" category and find which one goes with your spell. For example, the fireball effect would probably be named something like FireDamageFFAimed.

Oh, so I need to edit that effect itself. Find the effect, duplicate it, change it to a master level effect and then have my spell use that duplicated effect instead of the normal one, right?