You might actually benefit from deliberately introducing a small error in your Polar Alignment, yes, your stack may have slight rotation in it, but you might also be able to address part of the rain effect in parts of your image. But I agree with the previous poster, I don't think Dithering in 1-axis guiding is going to be very effective.
This is also the result without even know what is dithering.
This is a result of Stellarmate and 5px dithering. I think it is an improvement. Then I've read that in fact with DSLR people go even further with 10-15px.
So the 1st M33 is with Stellarmate and 10px dithering, then I had all those issues with Astroberry and Internal Guider dithering and tried the M33 above with PHD2.