ISO advice on equipment isolation

my gear currently resides within an audio rack with glass shelves--1/4" thick panels sitting atop rectagular metal frames bolted into two vertical metal side columns. I've been advised by one well-known audio dealer to swap the glass drop-ins for MDF shelves cut to the appropriate size and further to line the botom of the new shelves with Dynamat to decouple them from the metal frames on which they will sit. Another retailer tells me that MDF is not much better than glass and that I should go for "Baltic Birch" plywood and shun the Dynamat for something like the "grungebuster" dots sold by Herbie's Audiolab as a decoupling device. Still others say that solid maple is better for audio shelving... I'm not yet ready to spend big bucks on a new set of racks. Any advice from fellow Audiogoners on what to try? Most of my equioment is already elevated from the glass by eith Brightstar sand boxes or Mapleshade platforms. Thanks!
Do nothing. The Brightstar and Mapleshade products are very effective. Unless you go the DIY route improving upon them would be costly. As a longer term goal save up for a higher quality rack which will allow you to get rid of the sandboxes and platforms.
Well, First off do YOU hear anything that you consider to be a problem?

I use chemical butyl rubber bottle stoppers. size 10 between my glass shelves and the equipement feet.