Both of these were fairly unpleasant to listen to so I gave them a minute or two each. Stoyanov has a fuller tone and a fuller chest register but her voice is still rather thin and there‘s not even an attempt at girare when going above the stave making the sound harsh. She‘s also a bit wobbly, especially in the upper half of her voice. Yoncheva has the exact same problem but twice as bad so I’ll vote for Stoyanova but with zero enthusiasm.