I like the 3 because I currently only apply US while in a fulcrum hanging position, so the shaft is on the skinny side. Lol
If I was going to change up and apply US during a girth routine (I am kinda against this idea personally due to risk while restricting blood flow but I know others are in the process of doing DOE’s so we will see) or even length routines without being in a bent position, then I could see the possible benefit of using a 1 for a deeper penetration.
Worst case, if there is some concern with the 3 then you can always apply from both sides/180 degrees apart and you would be sure to heat the entire target area.
If I was going to change up and apply US during a girth routine (I am kinda against this idea personally due to risk while restricting blood flow but I know others are in the process of doing DOE’s so we will see) or even length routines without being in a bent position, then I could see the possible benefit of using a 1 for a deeper penetration.
Worst case, if there is some concern with the 3 then you can always apply from both sides/180 degrees apart and you would be sure to heat the entire target area.