Collaborate

The Collaborate skill is a Tier 1 skill under Jack's Greater Good skill tree. As the skill states, "Whenever one of your Digi-Jacks dies, you gain a stack of Collaborate, up to a cap of 10 stacks. You and your Digi-Jacks receive a 1% damage bonus per rank for each stack of Collaborate. All stacks are lost when your Action Skill ends."

Strategy
This skill can have a maximum of a 5% damage boost per stack and still only 10 stacks. To quickly gain stacks the character needs to run or move a decent distance and the Digi-Jack's will teleport the new position of the character. Though this teleportation will also count as a death of a Jack since it will need to redeploy. The only drawback is that this wastes the time of the action skill so to counteract this, combine this skill with the Best Foot Forward skill where once an enemy is killed the time running to "kill" the jacks is regained once an enemy is killed.

To maximize the stacks again is to let the skill run all the way out of time because by then there will be more stacks of Collaborate. Also to increase stacks before a fight that is in an upcoming bandit camp or some other area, activate the skill a bit before charging into battle, and let each jack run out of health once so there are two stacks before fighting. In most cases, the length of the skill will be longer than the fight itself so it's okay to only have half the time when the fight begins. Again combined with Best Foot Forward skill, the time lost will be partially regained.

Notes/Strategies Requiring Further Testing
I'm sorry to break third person but these are strategies that once tested can either be solidified or removed.
 * Using Jack's Promote the Ranks skill in the Hero of This Story skill tree will make it harder to increase stacks, since each Badass Jack has increased health they will lose health for a longer time before death. The part I'm unsure is if the health lost for each jack is just a percentage set so both the badass and the standard jack will die in the same time. If that is the case delete this note
 * Using Jack's You Have My Shield skill will make it harder for the Jack's to die but their automatic health loss doesn't get taken from the shield first. So the Jack's will die at the same rate as if they took no damage.