Note that this is a very difficult battle (if this is your first playthrough)--especially if you want to steal their items. Make sure your Steal character has high LUK (75-100 will be sufficient) or you will be failing most attempts. If you're lacking then you should be able to craft/convert items via alchemy to add more. Winfield's Hold Shot comes highly recommended to keep one or both of them at bay and for Steal/EX Stealing. Just make sure you stocked up on items prior to entering Vatna. To quickly add SP to Winfield (or anyone for that matter) is to use cheap-cost skills that buff/heal/restore the target character. Each cast gives 5 SP to the person using the skill and 5 SP to the person recieving the skill--so, for instance, Winfield would get 10 SP per skill used on himself. If you have everyone with at least 1 skill they can cast on each other then getting 50 SP for Winfield each turn should be no problem, as well as pumping up everyone else's SP on the side. Just make sure to have at least one person near enough to resurrect Winfield when he falls]. (As a side note, players may want to consider using Winfield if they haven't by now. He's a distance character with his gun weapon, he can steal quick and cheaply, he has decent growth rates, and he seems to be the only character in the game with a skill that can 'Immobilize', which can keep all but certain final/end game bosses from moving--with 100% chance of success. The description of his Hold Shot is slightly misleading in that it actually immobilizes (not 'paralyze') and (not 'or') attempts to steal with each use--the name of the skill itself is a better indication of what the skill -actually- does ('Hold' Shot). With the SP gathering and immobilization method mentioned above, you can easily dominate almost any boss fight and steal in complete safety while also maxing everyone's SP in the process.