I've reached a level where I have Blast 20, and skill points banked up for Blast 30. My conundrum is whether or not I should wait to get Blast 30, or start adding Holy Charge now, and get Blast whenever I can. I could of course wait until I have 10 SP stored to add the remainder as well. There don't seem to be any Blast 30 Mastery Books in the FM right now, and they drop from HT or Pap, which can only be done twice a day. So should I start adding Holy Charge, or wait until Blast 30? Thanks~!
You won't know when Blast 30 is going to be available so I would add points to Holy Charge. That way, you can increase your damage just by a bit since you should be around skeles level and they're weak against holy element. It'll make leveling faster and you'll gain back the 10 skill points needed for Blast in no time. Your goal is to maximize damage to level faster and holding onto your points isn't going to increase your damage. Also, be mindful that Blast 30 has a 50% pass rate. People have failed more than 10 times on these books.
If you're considering both these skills,I'm assuming you're still early in your 4th job. Go for Holy Charge and grind while you wait. Early 4th shouldn't be too rough and chances are you'll use Charged Blow more often than Blast.