I've been making commander heads since 2000, and there doesn't seem to be any solution other than keeping a stack of timber drop offs on hand to make more. And taking several extra heads ready for use to a raising.
My commander heads have been made out of eastern white pine, spruce, and hemlock. Some have split more than others.
I took one set of commanders to at guild raising where they told me that they were glad to see me as they had split and broken four commanders the day before I got there assembling the bents.
My job that day was to work with Dave Carlon and his crew adjusting and plumbing the post of this barn. Each post was 12"x12"x20' and they had to be moved to the correct distance from the outside gable was as well as the correct distance from the side wall.
I swung that commander all day long moving 4 post per bent in a seven bent barn. And never broke the head on it.
The very next weekend I took that same commander to a well know timber framing school to be used to raise the class frame and a student broke the head of the handle with the first three swings.
I believe it was due to operator error. He didn't understand that the end face of the commander has to strike the object timber flat. I think he hit it on a corner of the head.
I make my commander handles out of red oak, and have had the same handle for 8 years......
I have never suggested that anyone use a ring as I feel it will eventually fall off during use and that it could damage the timbers being assembled during a raising.... But that's just my opinion about rings....

Jim Rogers

Whatever you do, have fun doing it!