Pull-ups and different grips

I do 3 sets of weighted pull ups after each strong lifts day. I have been doing 1 set of pronated grip, 1 of supinated, and 1 of hammer.

Should I stick with one grip for a certain time and then switch to the other, say every week or so? . Or am I getting a good workout switching for the different sets?

I personally think you are getting a good workout. The biggest thing is to challenge your body. I would suggest maybe not using weight and going higher reps to further your work out routine. Or use more weight than usual and decease reps. Keep the body guessing. I work out with my friend and anytime I come close to the work out getting easy he makes sure to change it. I am a big believer of the P-90 logic. Good luck in your work outs stay hungry!

I do 3 sets of weighted pull ups after each strong lifts day. I have been doing 1 set of pronated grip, 1 of supinated, and 1 of hammer.

Should I stick with one grip for a certain time and then switch to the other, say every week or so? . Or am I getting a good workout switching for the different sets?

In my opinion, choose one grip and progress with that grip for all 3 sets. Put some form of progression in, so that you are hopefully gaining reps or weight over time.

Sounds great to me. If you want, do all three sets the same way and then switch week to week. But the way you do them is perfectly fine. If you want to have a greater effect on your biceps then do more sets close grip underhanded. But to each his own. You're doing fine and it sounds like you're improving. Great job.