Likely just one, covering the entire packaging system and all sizes. Prerequisites: each size truly has consistent materials, all suppliers have supporting evidence, and the packaging identification field states the coverage scope clearly.
Components to list: five-ply corrugated outer carton / printing ink / sealing tape / PE inner bag / PE collection outer bag (if pallet and wrap are separate, they count separately).
Who signs: you specify the overall package design → you sign. When specs stay in your control, you can use one declaration covering everything; if you let suppliers design freely, you're back to 'one per supplier.'
Strengths (actively state in documentation): no metal fittings, no logo, minimal ink, single-material, recycled paper—good design for recyclability. Carton and PE bags separate by hand, better than paper-plastic laminates.
Weaknesses and action items: • Two layers of plastic (inner + outer bag) may be questioned on necessity; document the reason (moisture barrier, contamination prevention, unitization and spillage control) and keep it on file • PE bag recycled content will become a hard requirement later; start asking suppliers now, no need to change materials yet
Possible improvement suggestion: if sealing tape is still plastic, consider switching to paper tape, turning the outer carton into a pure-paper stream and strengthening your recycling story; cost difference is minimal.