Self-Published Series - Book Cover Design System Needed

I'm redesigning the core visual infrastructure of a long-running nonfiction book series to be more modern. The covers came off Photoshop templates built years ago and they look it. I want a new design system, built once, that any competent production designer can execute across the catalog. What I'm actually buying is the system, not one cover. The deliverable is a design language plus the working files that let it be applied a few hundred times without re-hiring a designer for each book. The hard part is every cover features a photograph of varying levels of quality. That means the source images are wildly inconsistent — different photographers, lighting, eras, crops, backgrounds, and resolutions. Some are excellent. Plenty are mediocre. The system has to make all of them look like they belong to the same publisher. So the core of this job is a photo treatment system: whatever recipe — duotone, tinted overlay, knockout with a color field, consistent grade, fixed figure placement — makes a great photo and a merely-acceptable photo both land as the same imprint. The system also needs to: - Handle wildly variable title lengths, from one-word names to long subtitles - Signal clearly on the cover who the book is for by reader age, and that it's part of a series - Win in a thumbnail. Almost all of these sell off a small image in search results. That is the primary design constraint, not the printed object - Be easy to use for a less technical person with limited Photoshop skills I don't want AI slop - don't bother applying if you're not an actual designer. All artwork delivered under this agreement must be created by a human artist. The Contractor may not use generative AI image tools (including but not limited to Midjourney, Stable Diffusion, DALL·E, Firefly, and any successor or comparable tool) to produce, compose, upscale, or in-paint any part of the delivered artwork. AI-assisted utility operations that do not generate imagery — noise reduction, selection masking, and equivalent retouching aids — are permitted. Full deliverables at the system stage - As a test, we'll mock up 3 distinct system directions as concepts, each shown on the same 4 sample titles across different categories - On selection: a full style guide — type stack, palette system by category, grid, the photo treatment recipe written as repeatable steps, layout rules, spine and back-cover architecture, attribution placement, age/series signaling, thumbnail rules - Editable master template files (Photoshop, Illustrator, InDesign, or Figma — tell me which and why) set up so a production designer can drop in a new photo and swap title/subtitle without rebuilding - A written spec for how a non-designer briefs a new title into the system, including how to judge whether a supplied photo is usable - Production of the first tranche of covers against the system would be a follow on milestone potentially For the 3 mockups of this design system, I'd like to start out with a $125 fixed milestone test. This would be where we take a first stab at building what this might look like. The secret word is spine.