As was seen in his discussion of left hand position, for Harry Berv in A Creative Approach to the French Horn one central point is that of “compensation.”
Compensation for different sizes of hands
As a teacher he seems very aware of the natural variations of hand sizes seen among horn players and is concerned to tailor the approach to an individual student. But note as you read below that he assumes the bell is on the leg.
In teaching the correct placement of the hand within the bell, it is important to take into consideration the size and shape of the student’s hand. Some hands are short, some long; some fingers are very thin, others very thick. Here, again, my principle of compensation becomes crucial in executing this technique. I cannot stress too strongly the importance of this principle in playing the horn successfully. It comes into every phase of the teaching and learning process.
A horn player with a small hand must spread his hand without separating the fingers, to prevent escape of air. His tendency, at times, is to push the hand too far into the bell. This creates problems, particularly in executing stopped notes. The teacher must call attention to the maximum looseness of fingers a player can achieve without separating them. A very large hand must be regulated just as carefully, for it can block the aperture of the bell too much, causing a tubby, heavy sound that disrupts intonation. A player with large hands must be taught how to compensate by compressing the ends of his fingers without causing strain. But the final test of how effectively the player compensates for hand size is in the sound he produces and the quality of his tone.
The clock as an aid to positioning
Berv suggests a method of inserting the hand into the bell to achieve the correct position. In his discussion of this he explains the system by means of the “clock” system of gauging the position of the hand.
Visible on the exterior top of the bell is a brace, at the point where the bell is fastened to the main branch of the instrument. Because this point is right at the center top of the bell circle, I refer to it as “twelve o’clock.” Bear in mind that the thumb touches the inside of the top of the bell at a “one o’clock” position (slightly to the right of the brace). To place the hand in any other position would impair the natural movement of the wrist and would reduce the effectiveness of the hand placement.
The distance between the heel of the hand and the inner side of the bell, the one nearest the body, should be approximately 1 1/2”….