How do I prepare a clear financial and rota plan for a polygyny application?

Prepare a written plan that shows real figures and arrangements that can be monitored, not a general promise to be fair. Start with your net monthly income, then deduct your fixed commitments. Break the balance down into maintenance for each household: housing, food, utilities, and the children's education and medical care. Include emergency savings. For the rota (turn of nights), state the cycle you plan and how you will handle holidays and the Eid festivals. This plan helps the court assess your ability. More importantly, it helps you yourself see whether the plan can really work. If the figures are not enough, that is the honest answer. See polygyny readiness check.