Hi Rob,
what spinor want to say is “a color” on paper come from the relationship ink+paper+driver and the profile you download from epson is for the relation :
windows: ink ( epson original fro that printer)+paper (the paper you choose)+ code who drives the printer hardware ( windows code)
mac: ink ( epson original fro that printer)+paper (the paper you choose)+ code who drives the printer hardware ( Mac code)
Linux: there’s no ICC for ink+paper+driver relationship or put in another way … it’s unlikely you find an ICC profile with your Gutenprint driver setting…
Hence what is the solution??
You have to make your ICC profile by yourself by a spectrometer and Argyll FOOS software.
I hope to be been clear 
Cheers
Gabriele