By the time you buy a good mag float and spend the time, glue, etc...you might as well just buy a frag rack, IMO. Besides, egg crate is hard to clean.
The problem I'm having is that the Eshopps large rack only has two magnets and it's not enough to hold on 1/2" glass. If I bump it, it will fall. I have tried by buy one from Captain Saltys, since the small one I have from them works fine...but they don't seem to be very willing to sell one for some reason. They're listing them on ebay but when I did the buy it now, they cancelled the auction and don't give me any options to buy it.