I built a flatplan for a placeholder photography-led magazine issue. The running order has front of book, 8 features, two photo breathers and back of book, 128 pages in 8 signatures of 16. Each feature gets a treatment of grid, headline style, opener and image sequence; every page layout is derived from it, and every pair of features differs in at least 3 of the four. Six constants (body type on a 13 pt baseline, folios, margins, captions, masthead, palette) hold the issue together. A pacing strip plots image weight page by page; the build asserts no more than 3 text-led pages in a row, no full-bleed images meeting across a story boundary, and every feature opening on a spread. It also carries the type and grid specification, an asset intake tracker per story, and a production spec: 3 mm bleed, 300 PPI effective, 2787×3614 px for a full-bleed page, and spine width from page count and caliper (6.4 mm on placeholder stock).