So the best thing to do would be to start as a conjurer, do normal heals in dungeons from level 15 as soon as I can, catch a ride on the levelling train and run dungeons while there are people. Become a white mage, see what it is like in groups. Then grab a book and start from level 1 as an arcanist, this time the world a little emptier as most have moved on up the level ladder.

Mostly solo the arcanist until I can become a scholar at 30 and then do dungeons as a healer. This will then allow me to cross slot some white mage heals or play a white mage and cross slot some scholar skills.

Sounds good. Pity the arcanist can't hit dungeons early on, or I would play that from the start, the idea of more tactical smaller heals with debuffs and shields appeals to me more.