Yes (and No). I think it will be possible, because the text render and the outline is AFAIK rendered differently.
But that may require some change in synedit codes, so most probably not for now (Lazarus 1.8.4).
Anyway, your taste/preference is uncommon, we are mimicking the CNPACK and your requested feature is out of radar (unavailable);
but still good to have that choice with future Lazarus.