Shelf Help Lovan Rack

Personally, I think the maple platform will give you better sonics (anytime) over glass.

Just to clarify the maple platform would rest on top of the glass

Kill the glass completely. Go with wood. Sound on glass rings, rings.

One idea - replace your glass shelf completely with a Neuance shelf. You'll get noticable improvements in every aspect of your sound, especially under your table. I did this, one shelf at a time, and am thrilled with the improvements.
Google Neuance to find the link. Highly recommended!