b) in the main 3880 printer driver dialogue set "user defined" and "Off (no color correction)"
Yes, the answer is b, if your app is set to manage color, then you need to turn off color management by the printer, otherwise you would be applying the profile twice.
You could instead turn off color management in your printing app, in this case Qimage, and have the printer driver manage color, using whichever ICM you prefer. But having the app manage color gives you a much more consistant workflow.
You can change the default for the printer so that it comes up with color management off when you open it, by going to Control Panel, Devices and Printers, select the printer, then right click on the printer and select Printing Preferences... Anything you then select and OK, will become the default for that dialog. The same goes for paper type: the newly installed driver will default to Epson Lustre and PK, if you more often use fine art paper, this can lead to unwanted accidental switching of black inks.
Brian A