Hi Scott,
I propose the following experiment: at the beginning of imaging session, when you are already guiding and the first sub has been downloaded, zoom into your first sub in Nebulosity (400%) and mark a centre of any star by right clicking on it. (You can righ click many times to place more markers). See how the star behaves from sub to sub (of course you would need to do that without dithering). If the star consistently moves relative to the mark from sub to sub in one direction, you have a flex between the guide camera and the main camera.
Nonetheless, as I mentioned before, your last photo demonstrates a vast improvement over the first ones you took with this telescope