Triplanar mapping issues.

[sirio76]

I'm testing triplanar mapping on some shaders and I'm noticing a few problem.
Let's start from the standard shader using cubic mapping:
 

[sirio76]

Of course when the angle change there's an issue using cubic mapping so I insert all the texture inside a triplanar node, but the scale is wrong(more on that later) and the bump get inverted:

[sirio76]

In order to fix that I've inverted the bump intensity and scaled down the size inside the triplanar node, now works decently but why the texture size has to be set double the size of the cubic projection? to match a 15x15x15cm cubic mapping size I have to set the triplanar node to 30cm so please fix this and the inverted bump.
Also the texture sampling seems to be affected and no longer look like the normal cubic mapping. I've also noticed that by loading the texture for the triplanar node using a Corona bitmap loader, the bump issue get resolved but sampling looks far worst then before.