In the seven step preliminary in How to Practice a Meaningful Way to Life
By His Holiness the Dalai Lama:
Context on Homage: (pg 97)
Put your palms together, and feel intensely that you are respectfully taking refuge in the Buddhas and Bodhisattvas. Say out loud: "Homage to Shakyamuni Buddha and the Bodhisattvas. "
In my experience His Holiness always includes all Buddhas somewhere in his sections on "Homage" - they are never displaced.
However, I am sure that if anyone feels that their own "feeling intensely that you are talking refuge in the Buddhas and Bodhisattvas" (as HHDL teaches) is not powerful and intense enough, saying it out loud may help
- anyone can tweek it, saying it out loud may help to get to "feel intensely that one is taking refuge in the Buddhas and Bodhisattvas"