There are no differences in painting in Blender Internal or in Cycles, because the Paint Tool is exactly the same; the only difference is in the preparation of the materials.
In this recipe, we are not going to repeat the procedure already explained in the previous one; we'll just set up the file for the painting and test whether it's possible to paint in real time on all 5 image textures at the same time, as it is in Blender Internal (spoiler: it is).
Let's start with the
Gidiosaurus_painting_BI.blend file; in that file, we already have the UV/Image Editor windows set and the 5 materials assigned to the 5 different UDIM tiles and parts of the mesh.
In case you want to start with a brand new file, here ...