This is not a mod.  This is a tutorial for Xbox controller users that will help you do the following...  

• Enable southpaw (left handed) controls
• Allow 'change target' in vats when using southpaw
• Change the 'hold breath' button
  

The first step for all of these tweaks is to install the Fallout 4 Script Extender.  Take the 'CustomControlMap.txt' file included with F4SE and add it to your 'Fallout4' > 'Data' > 'F4SE' folder.  Make sure you keep a back up of this file in case you need to revert your controls.



---Southpaw---

Open 'CustomControlMap.txt' and look for the following sections near the top...


Move        0xff        0xff        0x000b

Look        0xff        0xa00        0x000c

The sections you need to change are the 3rd set of characters.  This is the Xbox Controller hexadecimal value.  You can see a list of these values at the bottom of the page.  You need to swap 0x000b (left stick) with 0x000c (right stick).  So simply change the 'b' to a 'c' and the 'c' to a 'b'.  Save the file and you're done.  You now aim with the left stick and move with the right.  However there is a drawback that you need to fix first...



---Vats target change---

Unfortunately, with southpaw controls you cannot change targets in vats.  To fix this, open up 'CustomControlMap.txt' again and look for the following sections...

NextTarget    0x44        0xff        0xff

PrevTarget    0x41        0xff        0xff

Just like before, you need to change the 3rd set of characters.  '0xff' means that nothing has been assigned to it.  Look through the list of hexadecimal numbers at the bottom of the page, pick your preferred buttons and replace '0xff' with them.  Do NOT change the '0xff' in the 2nd group (see picture tab for more info).  Save the file.  Bear in mind that certain buttons are already hard coded such as 'X' for criticals, 'A' for confirm and 'B' for cancel.  I would recommend using 'left stick click' and 'right stick click'.



---Change 'hold breath' button---

Again, open 'CustomControlMap.txt' and look for the following section...


Steady        0xa4    0xff    0x0040

Change the 3rd set of characters to which ever hex value you want.  However, be aware that certain functions will 'overlap' depending on what button you choose e.g. melee, vats, reload.  'Open pip boy', 'activate', 'change view' and the D-pad seem to be the only four options that don't overlap.  The 'hold breath' text on screen will still say 'LS', regardless of what button you use.  You will need to use a mod to change or get rid of it.



---Hex values---

D-Pad Up -------------0x0001
D-Pad Down -----------0x0002
D-Pad Left -----------0x0004
D-Pad Right ----------0x0008
Start-----------------0x0010
Back------------------0x0020
Left Stick Click------0x0040
Right Stick Click-----0x0080
Left Bumper-----------0x0100
Right Bumper----------0x0200
A---------------------0x1000
B---------------------0x2000
X---------------------0x4000
Y---------------------0x8000


Acknowledgements

• Hex values taken from 'fisnikhasani' (website no longer exists)
• A huge thank you to the F4SE team
  

*If you want to endorse, you'll have to download the .txt file in the 'Files' tab first.