People with the minhag should steadfastly continue following it. [snip] And those with a mesorah that does not include following the specified minhag, should not adapt it.
I assume you meant “adopt,” not “adapt.”
And that was the dilemma I was faced with on Shabbos. I don’t have a mesorah to say Yizkor during the first year and I don’t have a mesorah not to.
In the end, I said Yizkor.
The Wolf