The way that you will waste less is going on hunts.
If you're a druid find a team or ek to hunt. You'll spend a lot of mana with sio / spells. If you are a sorcerer go to hunts and use as much spells as you can. Ue, energy beam, energy wave, heal yourself with exura vita only.
If you want to maximize the training use the profit from the hunts to buy training weapons.
The % you can get in a single day depends a lot on your level, hunts and time available to spend hunting. But is is no where close to using training weapons.