I guess Pierre was exactly proposing a discussion in order to write the definitions.
Of course, one thing that may be used to disambiguate such cases is to symmetrize the lujvo, giving
something as
{spaselmikce} vs. {spavelmikce}, or
{selkemspaselmikce} vs. {velkemspavelmikce}.
It is very understandable, however, that such an obfuscated construction be avoided.
I liked gejyspa's idea a lot. Being it so concise, I even considered not defining spamikce at all.
In any case, I give my considerations for choosing a definition.
"Herbalist" is, to me, a more relevant concept than "doctor of plants" (it would be interesting to investigate if there is a special word for "doctor of plants" in some language). Nevertheless, I vote for s1=m2.
Firstly because I think it is a nice principle to prefer identification in the first places of the brivla rather than in the last ones. Ultimately because I don't think s1=m4 is a perfect identity, instead involving sumti raising of s1, inevitably leading to the concept of spapli. Marginally because I prefer killing the seemingly redundant {spabi'amikce} rather than the more natural {spaplimikce} ({spabi'amikce} suggests {spaselmicmikce}).
mu'o
mi'e .asiz.