Pat
I don't have much experience with soft frames. My information is based on watching Joerg get his flying and some of my older AQ quad I built.
Yaw problems can be caused by one motor that is not quite performing the same as the others. All your ESC may not be calibrated the same.
Trying to use your old settings is not a good idea.
We need to have a complete parameter list to do a good job of giving you some help.
Larry