Unfortunately the macron is the one missing dead-key accent on the US "ABC" layout. It's easy enough to hit the globe key when this comes up, but it annoys me a bit that Opt-y is ¥, and Shift-Opt-Y is Á, which is a duplicate: Opt-e-A will also produce it. I'd be happier if Opt-y was the macron dead key and Shift-Opt-Y took over for ¥: I can go a year without needing the Yen symbol, but it makes sense to have it. I don't think the English layout needs two ways to type Á though, it's excessive.