Over my years as an Atlassian Administrator I had the chance to plan, work and lead project migrations, instances merges and manage environments with more than 1600 projects. I've been the technical lead for decisions over this instances and defined several policies within them. Had the chance to work with different versions as well as windows/linux standalone environment. My experience has given me the skill not only to do advanced projects configurations but also to identify the best long term solution to this kind of implementations that due to Atlassian config flexibility you might have several ways to achieve the same thing but pay a high price by maintaining it over time.