Proposed new Lojban gismu

[cowan (John Cowan)]

I would like to propose a new Lojban gismu (root word).  The word belongs
to the culture/nationality group, but represents another culture closely
related to Lojbanistan's:  Esperanto.  Our current culture words reflect
the 12 most widely spoken languages, the names of the countries that speak
them, and a few other choices made for their wide inter-cultural use:
Greek, Latin, Hebrew/Jewish, Islamic.

The proposed word is "spero", meaning "x1 is Esperantist".
There is no other gismu sufficiently like "spero" to cause a conflict;
the nearest word is "stero", meaning "steradian" (a unit of solid angular
measurement) and we already have minimal pairs distinguished by "sp" vs.
"st", such as stali/spali.  "Ranto" is not usable as a gismu, because we
have "ranti" (soft).

All culture words must end in "o" and must have a rafsi, since the whole
point of a culture word is for use in lujvo.  There are two reasonable
rafsi:  "pe'o" and "pro".  Currently "pe'o" is assigned to "pendo" (friend)
and "pro" is assigned to "fapro" (oppose).  All other possible rafsi
are assigned to words that have no other rafsi assignment.

Three questions for this list:

1) Is the idea of a culture word for Esperanto sensible?

2) Is "spero" a suitable word?

3) Which is a better rafsi, "pe'o" or "pro"?