Thanks for the additional information Garie.
Assigning sRGB is correct for the OS you're using, so let's figure out what's causing the strange output.
When you opened the Inkseparation image in Photoshop- did you use the embedded profile, leave as is (don't color manage), or assign working RGB? Or, if you didn't receive this message when opening the image, please check your Photoshop Color Settings, and make sure they're set at RGB: Adobe RGB(1998), Gray: Gamma 2.2, and profile mismatch: ask when opening (these are the main important settings for your needs). Now, reopen the image and it should come up with the profile mismatch window- select "use embedded (don't color manage)". Then, select Assign Profile> sRGB. I attached a few screen captures below to show you these steps.
I am still waiting to hear back from Roy regarding the best workflows to print with Calibration Mode thru QTR Print Tool on different Mac OSs', so don't know exactly what to recommend, but can suggest what I would try (if I don't hear back from Roy, I will begin testing next week to gather some info for our users) if the above Photoshop workflow doesn't produce correct results.