User blog comment:Elite Red Viper/What Spell Costs the most Magicka?/@comment-4057437-20121029034441

It really doesn't matter as one can create enchanted apparel that reduces the cost of any school of magic to zero. Footwear is especially good as there are shoes that weigh zero. An assortment of dual-enchanted apparel to cover most needs would weigh less than four. (Hat = 1/2, shoes = zero, clothes = 2, gloves = 1/2, chain = 1/2, ring = 1/3. If using a circlet and a falmer helmet instead of a hat, the total is still less than ten, but won't be needed except for Alchemy).

Again, with dual enchanting, one can easily carry everything needed to cover several schools of magic. One's magicka could be one, and the spell cost 10,000 to cast.