No reason you can't collimate with the eyepiece and see how your subs look when imaging. Also, what your showing above is usable for collimation. I see the offset is towards the 3 o'clock position. The first dark diffraction ring thins on that side. Turn the appropriate screw to move the offset the opposite way. You know your turning the screw the correct way if the entire star moves in the direction of the thicker part. Make sure you recenter the star. Alternatively, to improve the definition of the diffraction rings, use a brighter star and/or a star at higher altitude. You may have to wait for a night of better seeing.
Finally, I've been using a tri-bahtinov mask for collimation when imaging for the past 3 years and it works great. Here's a link to the mask generator to have one made:
Here's before and after images of the collimation of my 9.25" using a tri-B mask:
Edited by Poochpa, 05 November 2019 - 12:28 PM.