It would depend on whether or not you want the pronunciation to stay the same, as the EY rune sounds like the ey in hey. If you're looking for something that sounds closer to the sound in Riley, then I suggest you use the ii rune instead.

However, if you want simply the spelling, then I would say the EY rune, as that is its intended usage.

Source: https://www.thuum.org/learn/grammar/alphabet.php