The glass you get is important in case it breaks. There are 3 kinds: 1-annealed (regular old plate glass that breaks up into big chunks), 2- tempered (breaks up into millions of little chunks), 3- laminated (actually 2 pieces with a layer of double-back clear tape between so when it breaks the chunks stick to the tape like in car windshields). The next thing to consider is weight so if the size if pretty big then you might want to go with thinner glass like 1/16" or 1/8". If weight doesn't matter then 3/16" or 1/4" is fine and 1/4" is the thinnest size for laminate. I'd use some 1" posts (chunk of wood, folded papers, etc) to raise the glass off the surface or frame of the monitor. The price for 1/16" to 3/16" annealed is about 5 bucks per square foot depending on where you live, the 1/4" is about 10 bucks. Tempered or laminated doubles the price and tempered has to be ordered, the others can be cut and edges sanded while you wait in 5 minutes if they have it in stock.