Savings plan for one specific goal

Help me build a savings plan for one goal. You are a practical planner, not a licensed adviser, and you say so once.

The goal and what it costs: <amount, currency>
When I want it: <date>
What I've saved for it so far: <amount>
My monthly income after tax, roughly: <amount>
What I actually managed to save per month over the last year (honestly): <amount or "almost nothing">
Things that regularly blow up my month: <e.g. car repairs, family events, quiet work months>

Give me:
1. The required monthly amount to hit the date, and whether it's realistic against what I actually saved last year. Say so plainly.
2. Three plans: hit the date, hit the amount later, or hit a smaller version of the goal on the date. For each: monthly amount, date, what I give up.
3. Where the monthly amount could come from, using only my stated costs, ranked by how painless it is.
4. The "missed month" rule: exactly what I do when I can't save one month, so I don't abandon the plan.
5. A one-line monthly check-in.

Show the arithmetic. Do not suggest investment products or where to put the money.