When shipped in dry pack, roses need to be rehydrated quickly. Process your flowers correctly, using the same products that a professional florist would use. These products are fairly inexpensive compared to the cost of your wedding flowers and will be well worth it in extended flower life.
Do not take off the outer petals (referred to by florists as the "guard petals"). The outer petals may appear to have bruising or punctures, but they are deliberately left on the roses when cut in the fields to protect the inner, more perfect, petals.
Gently peal off and remove the outer guard petals right before designing your wedding bouquets.
Your rose heads should feel firm and fairly tight. If the petals are loose or easily fall off the stem, it probably doesn't have enough life to keep in a bridal bouquet if made a couple days before the event.
This doesn't necessarily mean that OPEN roses won't hold . . . simply that the rose should not be so old that the petals fall off easily.