How to add a texture effet to the paint material ? (Real time render target painting)

Hello, I’m trying to achieve that kind of effect https://www.youtube.com/watch?v=Jz050a2OMXE

I have been able to do Real time render target painting with a sphere, but I can’t add a texture on it to change the splat effect form.
I tried different methods to add the texture but I always end up with weird circles, as if the texture was very deformed.

Here is my material. The green square is what I got to work.
Yellow and Red square are my failed attempt at adding the texture (UE4 logo)

https://forums.unrealengine.com/filedata/fetch?filedataid=119917&type=thumb

What did I do wrong, how can I have that texture to render correctly ?

(sorry for bad English)

Screenshots in game: green square -> yellow square -> red square

https://forums.unrealengine.com/filedata/fetch?filedataid=119918&type=thumb

https://forums.unrealengine.com/filedata/fetch?filedataid=119919&type=thumb

https://forums.unrealengine.com/filedata/fetch?filedataid=119916&type=thumb