Firefly just works on windows as you know .
Referring to this post , you can try Heteroduino and see if you can use it Firefly coming to Mac? - #3 by wim
I would have tried it for you if there was a mac with rhino installed nearby 
P.S. Please tell us if you tried it and got somewhere with it . And post if you find a way to handle this issue and tell us how :))