To install this mod there are couple steps. Add the included files to FAIRY TAIL\ShaderFixes\ folder.

Next, open FAIRY TAIL\d3dx.ini in notepad.
Press "ctrl+F", type the word "[Hunting]" (no quotes, yes brackets) into the search field, and press "Enter"

Paste the following text in the first blank line BEFORE [Hunting] :

[Key1]
Key = XB_RIGHT_SHOULDER XB_LEFT_SHOULDER
Key = VK_SPACE
x = 0, 1
type = cycle

====================================================================

That's it!, Save and you're done!
Press the space bar/key in-game to toggle the HUD on or off
For Controllers, press R1 and L1 at the same time. (Or whatever the Xbox controller has)

====================================================================

NOTE:
Do not put this folder (Toggle_HUD) or this README.txt in ShaderFixes folder.
Only the files with the word "replace" in their names go into the ShaderFixes folder.

Below is an example of what your d3dx.ini should look like after you are done.
The text above and below [Hunting] may be different. Please include [brackets] where necessary:

;convergence = 0
;$some_variable = 1
;transition = 100
;transition_type = linear

[Key1]
Key = XB_RIGHT_SHOULDER XB_LEFT_SHOULDER
Key = VK_SPACE
x = 0, 1
type = cycle

;------------------------------------------------------------------------------------------------------
; Shader hunting options.
; Default setup is to use keyboard similar to Helix presets
;------------------------------------------------------------------------------------------------------
[Hunting]

; 0: Release mode is with shader hunting disabled, optimized for speed.
; 1: Hunting mode enabled

====================================================================

Advanced: You may change which keystroke (keyboard) or button press (controller) toggles the HUD.
Alter "VK_SPACE" to any valid keystroke that is not already assigned a shortcut.
Alter "XB_RIGHT_SHOULDER XB_LEFT_SHOULDER" to change the controller button combo. Don't use one used by the game.

Link to Keyboard Keycodes:
https://learn.microsoft.com/en-us/windows/win32/inputdev/virtual-key-codes

List of Xbox keys:
    XB_LEFT_TRIGGER
    XB_RIGHT_TRIGGER
    XB_LEFT_SHOULDER
    XB_RIGHT_SHOULDER
    XB_LEFT_THUMB
    XB_RIGHT_THUMB
    XB_DPAD_UP
    XB_DPAD_DOWN
    XB_DPAD_LEFT
    XB_DPAD_RIGHT
    XB_A, XB_B, XB_X, XB_Y
    XB_START
    XB_BACK
    XB_GUIDE