When I acquired my first Stearman, and was learning to fly it, an old time Stearman pilot in looking it over said “ your seat belts are in backwards”. He explained that the release lever was pointed to the right instead of the left, as in the picture below.
When the release lever is pointed to the right and you push the stick to the left with your right hand, like in a roll to the left, your sleeve can catch on the lever and release the belt. This becomes distressingly apparent about the time that the roll puts you inverted.
Position the lever so that it points to the left as in the picture above, and it eliminates the Dreaded right hand sleeve catch!! (Shoulder straps left out for clarity)