I was taught that Yondan (in Wado Yodan) begins with the step out into backstance and with the hands in a "fishtail" to the side before rising slowly into the first move (Hidari Haishu Haiwan Uke). The key to this technique was the deceleration of the hands, performed with tension, almost like Seishan. In Wado, this move is fast and hard, and the arms don't drop into any prep before the first move. In Shotokan there is no shuffle or step before the second block, just a hip twist. In Wado, the feet move a "correction" distance, found in many kata that ensures the embusen is exactly symmetrical.
In shoto, we step forward from here into the X block (Gedan Juji Uke). In Wado the right foot steps up, hands to hips facing forward and then steps out with the left leg to make the X block and these first few changes are enough to trip me up and make my kata significantly weaker than someone of the same grade who has trained exlcusively in Wado. As with most kata in Wado there are both back-stance and cat-stances, where in Shoto you would usually see only the back-stance. Remembering to shorten my stance and perform only a single soto-uke rather than a double is another issue (this one is a real point of contention and the foot that kicks is the back foot, where all of the weight is placed which seems impractical), along with the final two moves being not Shutos, but kake-ukes.
This is from a book given to me by my sensei in 1988 to help me practice between classes - (note the high side kicks with uraken - not gedan barai and the double blocks)
For now all I can do is practice, practice, practice and hope that the N in my YoNdan can be erased over time.
Click the karateka to see the Wado Yodan performed correctly.