I can explain it pretty easily
so if you have the adapter plugged in there should be a bar of numbers in HIDtest
pretend this is it
11 11 11 11 11 11 11 11 11 11 11 11 11
Each 11 is an offset, starting with 0
if you press A then it would change to this
11 11 11 18 11 11 11 11 11 11 11 11 11
See how offset 3 changed to 18?
then on the controller.ini you should have A=3,18
Repeat this for every button
Analog sticks are a bit different
If you push the analog stick to the left and it does this
11 11 11 11 11 11 11 11 AA 11 11 11 11
StickX=8 (you just need the offset, not the value the offset changes to)
repeat for stickY, CstickX, and CstickY
you also need to add the sensitivity to the analog sticks. Adding ,0,100 seems to work for most. So stickX=8,0,100
Use this as a base
[Mayflash Wii U GameCube Controller Adapter]
VID=
PID=
Polltype=1
DPAD=1
Power=
A=
B=
X=
Y=
Z=
L=
R=
S=
Left=
Down=
Right=
Up=
RightUp=
DownRight=
DownLeft=
UpLeft=
StickX=
StickY=
CStickX=
CStickY=
LAnalog=
RAnalog=
Thanks for the info but I need to find the HIDTest tool