Fix proportions & greyscale on existing book cover illustration

I have a finished book cover illustration for my novel (AI-generated, based on my own detailed brief) that I’ve approved and locked in — composition, colour and content are settled. I need a designer to correct two specific technical faults only, not a redesign or new concept work.

Fault 1: The Pakistan silhouette’s proportions are currently too tall for its width and need reshaping to match a supplied reference outline — roughly 0.7 height-to-width ratio.

Fault 2: The two halves of the cover need genuine lightness/greyscale separation. At the moment they read as nearly identical in value; they need correcting to specific target grey values I can supply (Pakistan ~40% grey/value ~100, England ~60% grey/value ~155).
I’ll provide the full source artwork file, a written brief with exact numbers, and a reference outline image.

This is a fixed-price job only — please quote one flat total in pounds sterling for both corrections and final delivery of a print-ready file. I’m not looking for an hourly arrangement.

File specs required:
• Ebook/Kindle: minimum 1000×1625px, ideally 1600×2560px
• Print: 300 DPI, print-ready for a 6×9in wraparound cover including bleed, back cover and spine — roughly 4500×2775px or larger

Please confirm you can work from and modify an existing illustration file rather than creating new artwork, and let me know your turnaround time.
Also, worth saying — if this works out well I’d love it to be an ongoing relationship. I’ve other books in the pipeline, a hardback edition likely next year, and I’m looking to support other authors too, so there could be more work down the line.
Budget: Up to £100 (fixed price) for this specific correction work.