No Shuffle Steering
The current consensus is shuffle steering should not be used on road courses. "3 and 9" hand position makes shuffle steering unnecessary in virtually all corners, with the exception of smaller cars where there is so little space between the steering wheel and your legs that your knuckles hit your legs as you approach 90 degrees of steering wheel angle.
The biggest issue with shuffle steering is that when your hands are not on symmetrical points on the steering wheel (3 and 9 or 2 and 10) you don't know which position of the steering wheel is straight. This becomes important if you experience understeer or oversteer.
In an understeer situation, if you are not going to make the turn and are going to go off track, you generally want to go off with the front wheels straight to avoid spinning the car. In order to straighten the front wheels you naturally need to know what steering wheel position corresponds to the car going straight. This is trivial if your hands are on 3 and 9, and virtually impossible if you are shuffle steering.
In an oversteer situation, you generally want to countersteer which involves turning the steering wheel the opposite way from whichever way it is currently set. From having hands on 3 and 9 and applying, say, 90 degrees of turning right it is trivial and very quick to turn the steering wheel 90 degrees left. With shuffle steering you have to shuffle steer back - and this costs valuable time when you are trying to recover the car.
Lastly, while you are shuffle steering you have one of the two hands on the steering wheel, and if you have to apply steering corrections at that point it may be awkward to do. The result is delayed steering input which by now you probably have figured out is not ideal.