It took roughly 110 leves to get my alt character's miner from 15 to 50 using mostly evaluation leves and no buffs apart from food. 99 should be plenty for 30-50. but man was that tedious as hell. I always did levels +2 or -1 so that one of the items would be ~88% success with a +15% buff at 9 points a pop. Don't forget your daily GC turn-in, I finished off lv48 by turning in 10 HQ electrum ore as a starred item for a cool 200k xp.