A study from 2015 — “Elbow joint variability for different hand positions of the round off in gymnastics” — concluded that what I’ve heard called the classic T position is best and safest for the elbows when doing Round-offs.
I’d agree.
Of course you can quickly find examples of top gymnasts using far different hand positions, especially in MAG. But the classic T is what I teach beginners.

Via Shift Movement Science.