For unblocked diaphragms, the blocking requirements for floor and roof diaphragm bracing to transfer wind loads from exterior walls into the floor/roof diaphragm are based on the number of bay spacings required to get the load into the floor and roof sheathing. See WFCM 3.3.5 and 3.5.5.
For diaphragm blocking, does the number of joist bays blocked depend on the spacing of the joists or rafters (e.g., 16″ or 24″ o.c.)?