Filing a motion to modify allocation of parental rights and responsibilities?

I am attempting to complete paperwork to modify the current shared parenting plan that is in place. We currently are both designated as legal custodian and residential parent. The children split their time each week 50/50 with each of us. I am wanting to have myself designated as legal custodian and residential parent with him having parenting time every other weekend, etc. In my doent do I list all the reasons for wanting this change - difficulties in school due to missed homework, leaving school work/supplies and one parents and not having it, the father living in 6 locations in the past 5 years. Or do I just state I want to change to have the children live in a stable environment to promote their growth and well being. Should I wait to present my "evidence" of why this needs to happen in court? Please help