I am building a 20’x22’ attached Fiberglass pergola to my home. The ledger board is Fiberglas and a length of 19’. The pergola weighs approximately 700 lbs. The wind gusts can reach up to 50 mph, not including hurricane winds that can reach higher wind speeds. What lag screws (size and length) should I use if I am attaching the ledger board through vinyl siding and into plywood? Also, is there a certain pattern that should be followed (number of screws and distance apart)?