Best metod to paint a parameter from a sbsar

Hello !
I thought it would be something very straight forward since its a pipeline very comon in shaders but the way I do it doesn't do what I need.
So I made a material on designer that have a parameter to control an height blend node and my goal was to be able to paint on the mesh where I want the sand to cover my tiles like so :

But to be able to have this result and controle the scale of the material I had to put some tiling nodes inside my designer file before the height blend node because the texture I feed inside the parameter through an anchor is stuck in the UV space.

When I use the scale parameter of the fill material the painted mask is tilling too.

The process is very clunky in my case but I thought it was something essential for the designer/painter pipeline. I think I'm missing something here, do you have a better way to just paint a parameter inside substance painter ? 
Thx