I love both. [name_m]Emrys[/name_m] I would always pair with [name_m]Arthur[/name_m]: [name_m]Arthur[/name_m] [name_m]Emrys[/name_m].
But [name_m]Rhys[/name_m] is more accommodating and he makes a great addition to a double middle.
[name_m]David[/name_m] [name_m]Ewan[/name_m] [name_m]Rhys[/name_m], for example.