To add to the list of useful sparks options, take your trusts, jump on a job with moderately fast attack speed (I like using BLU for DW etc) and go fight the Qutrub Voidwatch mob in Arrapago Reef. He has a massive amount of HP, but he also takes a huge amount of extra damage to the point where you will never be less than 500 damage per hit. Most jobs besides BLU you can take Koru-Moru for Haste II (Arciela/King also work but they'll actually attack the mob) combined with one or both bards for Marches. Bring a healer or two and go to town on him. It's fantastically easy to cap sparks there. I haven't timed it so I can't say it can be done in an hour without finding out myself, but I know it's a tried-and-true method.