Assigning /voi/ to {poi'i} -- excellent stuff! I'm delighted to hear it's being used already. Rereading today some discussion from 12+ years ago, I see {se ka} was also proposed, subject to instigation of a convention for coercing added sumti places by addition of SE or FA.
Is there a list of cmavo recycling proposals? I saw somewhere a proposal to recycle /du/, which I was initially a little consternated by, since {le du} had seemed very useful to me (as meaning unbound "he, she, it, they"), but I guess that could be got by {lo co'e}, with {co'e} meriting a monosyllabic form.