In Deuteronomy/Devorim 17:14, and 17:18-20 we see that a king of Israel is required to write a copy of the Torah to read and keep with him always.
Would a convert to Judaism, who is a king of another nation (i.e. not Israel/Judah), be required to follow this mitzvah? Would it make a difference if the majority of the citizens of his nation were Jewish, and/or if he felt the land he ruled was given to him by G-d (Devorim 17:14)? (I'm asking specifically about a situation with a convert because I'm unaware of royal families with Jewish lineage in the modern day.)
I am assuming this is a separate issue from the other similar mitzvah (Deut/Devorim 31:19), as several people seem to comment that a Jewish king of Israel would need two Torahs, and thus a convert King would at least need one copy. For example, see below.
"The Gemorah (Sanhedrin 21b) relates that the king, in fact, maintained two Sifrei Torah. One was carried with him at all times, and the other was stored in his treasure room. The Rambam notes that if the king inherited one Sefer, he would write the second one on his own. If, however, he did not own a Sefer Torah, he would be obligated to write two sefarim." http://www.torah.org/advanced/torah-thoughts/5767/shoftim.html
Would it be acceptable/preferable for the king in the example above to keep his personal (Deut/Devorim 31:19) copy of the Torah in a synagogue, rather than a treasure room?
Please note that I can't read Hebrew or Yiddish.