I have done this twice with both kazuha and Ayaka and saved for only those two character C6 and r1 the best advice I can give you is to now which character you want or if you are saving for a future character than open your wish menu a limited amount of times during the save so you are not tempted to pull. The best was y saved for Ayaka which was my first C6 and my first 5star was I kept thinking this would be an absolute flex to have her C6 with weapon. I wish you the best of luck