actions to initiate the RTO functions.
Close the thrust levers, simultaneously disconnect the Autothrottle,
Deploy the speedbrakes
Max reverse thrust (as appropriate)
Closing the thrust levers geets you into the RTO braking, which will be more than sufficent to stop, assuming correct speeds and performance are being used.
Deploying the speedbrakes- ensures any/all lift dumped.
Reverse thrust is purely an additional item in the performance. It makes no difference to the RTO braking effort, unlike the autobrake functions.