NEC Rule for Sizing Star-Delta Contactor

90.1 (C) Intention. This Code is not intended as a design specification or an instruction manual for untrained persons.

110.3 (B) Installation and Use. Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

430.22 (C) Wye-Start, Delta-Run Motor. For a wye-start, delta-run connected motor, the selection of branch-circuit conductors on the line side of the controller shall be based on the motor full-load current. The selection of conductors between the controller and the motor shall be based on 58 percent of the motor full-load current.

430.32 (A) (1) pp 3; Where a separate motor overload device is connected so that it does not carry the total current designated on the motor nameplate, such as for wye-delta starting, the proper percentage of nameplate current applying to the selection or setting of the overload device shall be clearly designated on the equipment, or the manufacturer's selection table shall take this into account.

The NEC ruling is general; equipment must be appropriate for the use (couldn't find that one off hand). The NEC does not tell manufacturers how to assemble products. You must contact your preferred supplier to size the components appropriately listed for the motor.

But in general, the contactors can be sized for 58% of the motor HP (as inferred in the above references), sized up to the nearest level. Technically the shorting contactor can be smaller (33%), but in many cases the mechanical interlocks will not match dissimilar contactors and they all 3 must be the same size. That's why you must use the mfr's recommendation.