Den glass I recommend for higher end pieces. It filters out a lot of the sun's rays, and does not reflect as much, thus giving you a better view of your piece from all angles. I use den glass a lot for my personal pieces. Where to display Display your pieces much as you would any other valuable art. Make sure that you keep your pieces away from extreme or fluctuating temperatures.
Sunlight is also to be avoided.
I would use at least two hooks separated somewhat so that you can adjust the frame without it tilting. Also protects in case one hook becomes faulty. Store framed, unhung art wrapped in bubble wrap, and stacked vertically. If you do not have your framed pieces protected, store them verticle face to face, and back to back to avoid any nicks caused by framing hardware. Framing Materials Acid-free is the place to be.