I guess u should do like maybe about 3-5 sets to failure per session, if youre progressing well you can try out a few more and watch if you still can recover. If you goal is just to get very Strong you should do Most likely max 5 reps, if you also want a bit hypertrophy, I recommend like 5-8 and then you can add a bit extra wheight in the first sets as soon as you can do more then 8.