I’m not sure about most optimal, but I got around 55-60K xp/run in SP from level 55-58 (then I just went to Hellfire Peninsula and quested/rand dungeons). It was between 30g~50g/run, and I used gold I had acquired while leveling.
Yeah, I think it’s better XP than Strat, too. But, not all mage boosters are the same. I kept a record of my boosts, and some were only giving like 40K, others 58K+, but different prices.
Your numbers are based on guides. In reality, Mara can get you to like 52. You can do SM from 21 to 45. ZF isn’t as efficient, but can fill the gap or change your scenery if you’re bored. Strat kind of sucks in my personal opinion. I’d rather go quest Winterspring than sit in Strat boost.
How do you fill the gap between 45 - 55 cause I can do either SM/Mara to 45 and at 55 I can just do SP apparently, so that gap is why I thought Strat would be efficient.
If you have a really efficient booster that isn’t charging you a lot (so someone you know), then I would stay in Mara until level 51 / 52. If you don’t have that option, the Hinterlands are a pretty quick grind to 50, then Un’Goro to 55. Un’Goro can feel like a slog, but it’s not bad.
You can buy sp boosts once you no longer need argent dawn rep from strat, after you no longer can get rep from sp in ce you can head to hellfire. Cost wise I would do sm until lvl 42-44 then do mara until 45. Or do stocks until lvl 28 as it unlocks summons from sm stone.