To actually guarantee melting then you need to heat to the highest melting point of whatever ester has the highest melting temp.
Solvents like BB do help keep the hormone from re-crystalizing and they do to some extent help "melt/dissolve" the crystal structure and do help lower the temp where this melting happens but to guarantee a full melt we still need to get to melting temp. (As I understand it, and I am not a chemist or anything)
I have messaged with another brewer, I am personal and friends level, the other brewer was distribution level and claims (I believe) you can't cook the hormone off like people parrot all over the net. Think about it if the melting point is 120 then heating to 130 or 140 isn't going to burn or evaporate the hormone. Now depending on the carrier oil you can start to oxidize the oil if you cook for high enough and long enough but that is just the oil starting to attach to oxygen, not going rancid. I usually don't see the oil change color or oxidize unless I am brewing oil winny.