It's interesting to see how people can have different thoughts and ideas towards meditation
I am not sure if the tibetian Buddhist you describe has religious reasons to say it is important to stick to a certain mantra, or that he finds it working best, but I have switched mantra twice and switched from watching the breath ( used to do Zen before I discovered this site ) to mantra meditation and back and back again over a year's time, and am quite happy with the results.
From personal experience I would say: You could pick the word "Teapot" as a mantra, as long as it works, use it, otherwise, try something else !
However I could be doing something structurally wrong this way and that monk might be right all along
That wasn't usefull I guess... sorry about that !
