Tales of Adventure MSQ and Job Level which one to do first?

[Iscah]

Another thing if you're looking at buying a job skip but not an MSQ skip... as well as arcanist's two-jobs-for-the-price-of-one effect mentioned above, the most efficient jobs to buy if you want to play them ASAP would be astrologian, dark knight or machinist, as these aren't naturally unlocked until you reach Heavensward.

Also, whatever job you boost, you will effectively get Lv50 red mage, Lv50 samurai, Lv60 gunbreaker and Lv60 dancer along with it, because being Lv70 will make you eligible to unlock those classes as soon as you can access the cities where the quests are located - one of which will be your starting city, and the other two accessible at Lv15 of the story.

(Also I'd recommend Ul'dah for your starting city if you're not skipping story - it has the best of the three early-game storylines.)