I play this game on the PC with the PS4 controller (Dualshock 4). And I always found it tedious to switch to different signs using the radial menu. It's too slow and it breaks the fluidity of the combat. I know that you can switch to different signs using L2+left/right in combat to switch signs, but even that is not as efficient. I was just not bothering with switching to different signs, and just sticking with one of them.
So, after reading a few resources like reddit, a user there was using the following setup, and I decided to try it out. And I can tell you that it works amazingly.
The idea here is to switch Signs by using the swipes on the touchpad of the DualShock 4.
: Swipe Left - Yrden
: Swipe Up - Aard
: Swipe Right - Igni
: Swipe Down - Axii
: PS Button - Quen
I also added the following for convenience.
Touchpad right bottom corner press - Opens Map
Touchpad left bottom corner press - Quick Save
See the following images to replicate my setup. I am using DS4Windows 3rd party software. Make sure to select scancode when mapping controls, and if you're having issues, start the application as administrator. Hope this helps out a few people
UPDATE:
Thanks to sundaypostman, I've now changed to using the R2 + face button for using Signs, which I believe is superior to using the swipe method, as these combos instantly cast the spell.
My current setup is:
R2 + Triange = Igni
R2 + Circle = Axii
R2 + X = Quen
R2 + Square = Yrden
R2 + PSButton = Aard
Touchpad Click = Quick Save
Touchpad Right Touch = Map
Multitouch = Right Trigger (This was added to see detailed stats on character screen)
A 3rd party application called InputMapper was used for this.