I can’t get my head around the projection / resolution issue, I’m already using udims and (as you can see on the right) the textures resolution is fine. I’m already painting on an 4k Channel/canvas size.
But yet there’s seem to be a resolution problem when i try and paint onto my model. (see red circle)
Hi GreyEdzi,
It looks like this blurry part is located in another UDIM and this tile does not has the same patch size as the hires part. In Mari you can set the the UV patch size individual for each UDIM. So maybe the first UDIM is set to 4k en the second UDIM is set to 1024 or lower. Just right click on the UDIM and select resize patch size. I hope this is the problem 
goodluck
Jonathan