I would model my speech on the most neutral and standard accent of the
country I was going to live in. If not traveling there, I would
base it on the accent of the English speakers I would be in contact
with most as part of my job.
CJ
(By the way, here's a completely technical point:
speaking English with his or her native phonemes
is an anomalous idea. A phoneme is impossible to say or hear; a
phoneme is an abstraction. -- But no big deal; everybody knows
what you meant!)