The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
Read up on Starting Strength 3rd edition if you can. Most people can handle a knees under hips stance, however, if you sport proportionally longer femurs or tibias then you may have to widen your stance or pull sumo. And yes, I have seen several clients exhibit valgus during their deadlifts. Just make sure you enter and exit the tunnel in a good position!