That's a good koan, Joe. I would say: just pick a method, and go with it to the end of the world.
To emphasize your point:
Old case wrote: One day when Nangaku came to Baso’s hut, Baso stood up to receive him. Nangaku asked him, “What have you been doing recently?”
Baso replied, “Recently I have been doing the practice of seated meditation exclusively.”
Nangaku asked, “And what is the aim of your seated meditation?”
Baso replied, “The aim of my seated meditation is to achieve Buddhahood.”
Thereupon, Nangaku took a roof tile and began rubbing it on a rock near Baso’s hut.
Baso, upon seeing this, asked him, “Reverend monk, what are you doing?”
Nangaku replied, “I am polishing a roof tile.”
Baso then asked, “What are you going to make by polishing a roof tile?”
Nangaku replied, “I am polishing it to make a mirror.”
Baso said, “How can you possibly make a mirror by rubbing a tile?”
Nangaku replied, “How can you possibly make yourself into a Buddha by doing seated meditation?”
And, because we were talking about shikantaza, I'll add Dogen's comment:
Dogen in Shobogenzo chapter Kokyo wrote: For hundreds of years now, many people have held the view that, in this story, Nangaku is earnestly endeavoring to encourage Baso in his practice. This is not necessarily so, for, quite simply, the daily activities of the great saintly teacher were far removed from the realm of ordinary people. If great saintly teachers did not have the Dharma of polishing a tile, how could they possibly have the skillful means to guide people? Having the strength to guide people is the Bones and Marrow of an Ancestor of the Buddha. Even though the tile was the thing that came to hand, still, it was just an everyday, household object. If it were not an everyday object or some household utensil, then it would not have been passed on by the Buddha’s family. What is more, its impact on Baso was immediate. Be very clear about it, the functioning of the True Transmission of Buddhas and Ancestors involves a direct pointing. We should truly comprehend that when the polished tile became a mirror, Baso became Buddha. And when Baso became Buddha, Baso immediately became the real Baso. And when Baso became the real Baso, his sitting in meditation immediately became real seated meditation. This is why the saying ‘polishing a tile to make a mirror’ has been preserved in the Bones and Marrow of former Buddhas.
Thus it is that the Ancient Mirror was made from a roof tile. Even though the mirror was being polished, it was already without blemish in its unpolished state. The tile was not something that was dirty; it was polished simply because it was a tile. On that occasion, the virtue of making a Mirror was made manifest, for it was the diligent effort of an Ancestor of the Buddha. If polishing a tile did not make a Mirror, then even polishing a mirror could not have made a Mirror. Who can surmise that in this act of making, there is the making of a Buddha and there is the making of a Mirror?
Further, some may wonder, “When the Ancient Mirror is polished, can It ever be polished into a tile?” Your state of being—your breathing in and breathing out—when you are engaged in polishing is not something that you can gauge at other times. And Nangaku’s words, to be sure, express what is expressible. As a result, in the final analysis, he was able to polish a tile and make a Mirror. Even we people of the present time should try to pick up today’s ‘tile’ and give it a polish, for ultimately it will become a Mirror. If a tile could not become a Mirror, people could not become Buddha. If we belittle tiles as being lumps of clay, we will also belittle people as being lumps of clay. If people have a Heart, then tiles too will have a Heart. Who can recognize that there is a Mirror in which, when a tile comes, the Tile appears? And who can recognize that there is a Mirror in which, when a mirror comes, the Mirror appears?
Boy, he sure liked to write