Item Crafting/Enchanting/Spell Crafting Rules
1) First things first! You need Gold to make things! Once again so we don't have every Nord and Khajit with pseudo cowls of Nocturnal.
2) Follow the templates! In all reality you can do whatever you want with you're weapons/enchantments/spells as long as you have the coin/energy for them.
For example:
Little Timmy is a brutish Orc who sucks at Destruction magic and he has crafted himself a Master Tier Firespell that can literally nuke an entire city with a heat wave. He is now poor and is to ignorant to use the spell/ nor does he have enough mana for it.