another question related to the previous post. The wall tile will only be 20 in high (countertop to cabinet bottom). Someone suggested that I cut out the drywall (all 25 ft) and replace it with wonderboard. They said that the tile might be too heavy and the verabond mortar might weaken the drywall so that all the tile might just break off in one big sheet. I can understand using wonderboard if you were doing a complete wall but, is it necessary to put the wonderboard up for such a small height (about 3 tiles high)?