Ok... I want to use the 450k exp on prayer (duh, who wouldn't), but I am currently only 73 prayer. Do I need to get 75 before I finish the quest, or can I come back later for the reward once i get 75 prayer?

After the quest you can speak to Brundt any time for your reward, which comes in three lots. So the answer is yes, you can come back after you get 75 prayer.

Thanks so much!

Huh. I forgot about that quest... I have the fair majority of the pre quests and all of the skills needed, i think i might just do this for the prayer experience before i waste all my money on turmoil :P

 

Thanks for bringing this up and reminding me, lol.

 

(It's a shame you can't use it on summoning xp instead)