If you could move the bookshelves to the center shelf that would be closer to your ears.
I had used my center on top of tv for years, then when i got a bigger one I tried above on top of the entertainment center (too high) then i placed it on the floor aimed up, on a stand (best so far).
Dont worry about sheilding most if not all centers are shielded.
Angling up or down to aim at ears will give you a good presence, experiment when you get the center.
Dont get something with 4" or smaller woofers though, it will not please you.