I don't really know anything about zero cost reduction. I don't know how to do it - but you are saying I am better without it? I don't want anything to be too easy (hence the master difficulty).
Well, once enchanting is at least lvl 75 (I think? need to be able to enchant 5 articles of clothing...) you can easily enchant clothing enough to fortify destruction to zero magika cost. It depends how you want to play it. You could go this route as I chose my first play through as a mage (IDK if I would do it again). The reason I did it is because destruction spells are very weak, even expert spells are weak compared to an ebony bow and arrows are very abundant, magika runs out very fast.
That said I put all my lvl ups into health and very few into magicka. Not wearing any armor I did not want to always get one hit by everything lol.
I have yet to try how it would feel if I put more into magika, maybe I would not feel as restricted. More lvls of magicka and enchant clothing to fortify health and magika.
There are quite a few routes to go, many of which are probably viable.
IMO, having tasted zero cost destruction, my next mage will likely not go that route. IE put more lvl ups into magika, rather than so much health.