yeah, very nice! Super clean looking
Do you check your histogram after test shots to see where the hump is sitting? I'm still getting to grips with it all, but I saw a video somewhere showing that yeah, you do a test shot to make sure the guiding can handle the duration, but also check the histogram to make sure you're optimising exposures... I think it was astrobackyard from a fair while back.
Just noted you used no darks... amazing! My 550d would have massive hot beehive in the middle of the image. (I reckon, though, darks might be the go if/when you do go a bit harder on the ISO?)