Non plat doesn't mean you can't use elixirs.Btw, I remember you posting that you don't need to buy plat to be a high level somewhere. How do you level up without lixing? I find that insane.
Non plat means you don't personally buy plat. You can buy elixirs off people with gold and use them yourself.
Being a non plat isn't too hard, the main idea is just being smart with your gold. Bossing, merching, and dicing are the 3 big ways you can make gold. Bossing is 100% safe but can be slow at times. Merching is generally pretty safe but you need knowledge about prices, and it can also be slow but is generally faster. Then there's dicing which is still safer then not(60% chance to win as host), but the odds can still make you lose too, it can be slow too, but there's a fair chance to make good gold.
Personally I'm a merchant, and a while ago I used to hunt bosses too. You can do any of the 3, or any mix. As long as you are smart with your spending you should come out ok.
As a non plat and ex endgame player myself, I'd be glad to answer any extra questions if I didnt hit all the topics.