...I bought new, very expensive thread ( Superior ) and new, very expensive needles ( Superior ) to go with my newly serviced machine ( my machine won't tolerate Guttermans )
I'cw mentioned it before, but for me Gütermann thread has turned out the be the most even quality and trouble free of them all (sew-all polyester). I've had the top stitch and extra strength threads too and it is high quality. I have their cotton thread as well. The polyester threads leaves much less dust than any other brands. I like most mercerised cotton threads though and I'm not that picky, neither are my machines.
Do you have a simple straight stitcher or other machine for backup? Sometimes it can be the machine, not ideal for some types of work. The odd thing is the Gütermann thread, at least sew-all polyester. It's common for a machine not to accept top stitch threads that well; some need a special bobbin case for it.
You have to check the bobbin tension when switching to a new thread, they are all different, weight, thickness, smoothness. I guess your Innovis has auto tension for the upper thread?