I just finished changing the radius myself. Thought I’d post in case anyone else find this post as I did, top of the list from a quick google search. The entries are under "WorldObjects\Light" in the CK. You'll need to edit “MagicLightLightSpellHand01” for the candlelight spell. "MagicLightLightSpell01" should do Magelight if you wanted to change that, but I haven’t confirmed it yet.