simplesimon,
I practice yoga and have heard many teacher talks over the years. My impression from the talks was that Hari can refer to many entities, though generally Krishna.
But when I googled "hari hinduism", it appears that Hari applies both to Vishnu and Krishna, and Krishna is more often considered an avatar of Vishnu than the reverse.
So either could be used? Krishna
would fit better with the Gita reference.
Maybe I'll post an alternative, but likely not merited given the strong field.