I like to use the smaller A5 storage panels since I prefer all my sets to stay together and stored one set to a panel. My head is geared to thinking in terms of sets, not images. (Disclaimer - I only have SU! stamps wood mounted. Other brands of stamps I buy as cling mounted and most times need a different storage solution).
If you not satisfied with your current arrangment with the stamps then it is good to change it to fit you. Diane, your arrangement looks very sensible and user friendly.