Looking for Help with the Pressure Sensitive triggers for GCN Controller

[MagicC4ke]

So, I went onto Ebay and bought a USB GameCube Controller specifically to play GCN games on Dolphin.

Then I went to play Super Mario Sunshine and I needed the pressure sensitive triggers to play the game properly.
I went into the options and already binded the same L + R triggers to the L + R Analog settings, but it hasn't done anything to help.

Am I best off just using the R Analog as a separate button for Sunshine? Or is there a fix?