I have been thinking about that, too. I had been using a 12 for the halos, but recently switched to a 16. Strength wise, the 16 does not seem difficult, but my left shoulder is starting to bother me. I am going to move back down to the 12 for halos and see if that clears it up. I would eventually like to move back to the 16 for halos, but being pain free is more important.
I started off using the 16 for goblet squats, but recently moved up to the 24. This feels good and I will probably stick with this for a while.
I am currently using the 24 for swings and the 32 for getups. My lower back is starting to bother me. It never bothers me during my workout, but will hurt in the morning. I kind of have a feeling that the getups are irritating my back, but it am not sure. I am going to go back down to the 24 for getups for a few days and reevaluate. The 24 seems so easy it doesn't feel like a workout.