Based on Goku’s appearance in the Cell Games arc when he could maintain his Super Saiyan form permanently, the Full Power Goku includes alternate hands for posing him ready to blast a kamehameha ...

Only Goku has mastered Kaioken, using up to x20 but never combining it with Super Saiyan. Combining Kaioken with SSJ is risky due to the emotional stress of SSJ affecting ki control.