Everyone is talking about the way Gavito is seen in the pic holding the palm. It is not something I will do and I see very few hold that way. I haven’t seen anyone teaching a hold like that.
But whether it is comfortable or not, can only be said by someone who has danced with him. Things looking uncomfortable to observers and actually being uncomfortable are two distinct. Problem also occurs when they get copied by those who do not know better and cause discomfort. A hold like that is likely to go wrong in several ways making it a cause of discomfort to cause of pain.
For that hold not to feel uncomfortable the position of arm and elbow, tension in the arm, etc are vital. It is less forgiving of the holds.
I have tried it (why not), and it works.
I do not have one standard way. I adapt my hold to the partners ability and try to get to something optimum. With some rare partners I dance with the palm above or at her head level. With most it is between the ear level to shoulder level. With a few it will be below shoulder level. It really depends on the partner.
If talking about just the palms, like everything else in the body, people have different anatomies and anatomical flexibility. For example my palm can twist backward further than most people. My right plam is able to twist a bit more than my left. So something that works for me will not work for you. Some followers keep their fingers and palm light that if you don’t provide support they start slipping to the base of the palm. It amazes me how they are either not aware nor try to correct it. I watch them with the other leaders after that and it is the same.
My conclusion is the only universal rule is don’t hurt and don’t make it uncomfortable for the partner. Other than that there is no universal rule for how to make a hold. Of course from pure aesthetics and functional needs, certain guidelines work better.