Hey Ammy. As far as how I've been building my priest on Hats, I find soloing content and heal bombing Undead monsters to be the most efficient for your early levels. Therefore, you want to only put points into INT for a while. Slower monsters with no ranged attacks will let you get away with this and not having any VIT (Skeleton/Zombies in Payon dungeon 1, Megaladons in the east entrance of Comodo, Orc Zombies/Skeletons in Orc dungeon 1) into your 50s and 60s. You can be pure INT (around 70 INT) before you have to consider putting points into VIT.
Another tip for early acolyte leveling is to have 2 different hotkeys for Heal at different skill lvls. Like Heal lvl 10 and Heal lvl 4. You use Heal lvl 10 to heal bomb, and Heal lvl 4 to heal yourself. You can even heal bomb say a Skeleton at Heal Lvl 10, then hit it with the weaker Heal Lvl 4 for more efficiency if the combined damage still kills them. Why spend 40 + 40 SP to kill something when you could possibly just use 40 + 22 SP instead? Experiment with it.
I'll keep an eye out for you this weekend (when I can play at the same time as you) and we'll work on how to solo as well as eventually learning how to party with people. Other low level characters also invited.
I'm personally going abnormally high INT first as I'm soloing a lot with Judex and not really needing the VIT as much even with minimal gear. Currently at around 110 INT, 70 VIT, 70 DEX at around base lvl 109.