That's some pretty good stuff, right there. Out of curiosity, any reason you're using HSTORE instead of JSON? I've been watching what contexts JSON gets used in PostgreSQL systems, and having another data point never hurts. :)
That changed with JSONB, which got introduced in 9.4 - that's essentially HSTORE2, with additional improvements.
HSTORE vs. JSON: Lower storage overhead, faster operations on stored data.
HSTORE vs. JSONB: Significantly lower storage overhead but more limited