I’ve released as a standalone example an adaptation of the PIDController class in WPILib that can be used in conjunction with WebDMA to allow interactive PID Controller tuning. Its a definite time saver if you’re new to tuning PID stuff, or just want to see the craziness that ensues if you wildly change your PID parameters. 
On a more serious note, we used this last year to assist with tuning of our 4 custom servos that we created for our swerve drive.
If you look at the WebDMA demo site it shows an example of the type of web interface (with P,I,D variables) created by WebDMA.
Download link for the ProxiedPIDController class
I hope you find this useful, and happy PID tuning!