Test the finished width, height, thickness, fold direction, paper finish, leading edge, and tab position. The mail piece should feed consistently without curling, opening, or shifting as it passes through the applicator. Coated stocks and heavy folded materials may respond differently from plain paper. Prepare samples using the actual printed and folded job, then run enough pieces to confirm stable feeding rather than testing only one item. Check that the tab adheres firmly across the fold without covering important text, addresses, barcodes, or design elements. Mailing requirements may vary by format and destination, so confirm current postal standards separately. Record successful settings for recurring jobs to reduce adjustment time and material waste.