Start with where the pennant will be seen and how people will use it. A small handout, an individual keepsake and a wall display need different proportions.
Choose the job before the size.
For a welcome pack, compare the pennant against the other contents and the package. For a merchandise table, consider how it will hang or stand. For a wall, measure the available area and the normal viewing distance.
Compare the shape around the artwork.
A classic triangle gives a long name a familiar outline. A swallowtail introduces a forked end. A custom shape can follow a badge or mascot, but narrow tips, cutouts and hanging points need a construction review.
Use dimensions as a planning aid.
A 4 × 9 inch mini and a 9 × 27 inch classic show how much the available artwork area can change. Treat these as example formats, then confirm the exact dimensions on your proof and quote.
Include the entire display.
A cord, header, stick or ribbon changes the space the finished item occupies. For a string banner, specify both the flag sizes and the complete cord length, including the end ties.