You are correct that the Aquia II, Aquia III, and Carlyle require holes to be drilled for the Unifit adapter. However, this is not really too difficult provided you get the right drill bit to go through the tile. They take about an additional 1/2 hour for a plumber to install, homeowners likely more especially on the first one. The Ultra Max would also be a good choice and it does install in the conventional way. Both Aquias are dual flush, the Carlyle is not, nor is the Ultra Max. So, your dilema continues (LOL) The good thing is, you can't go wrong with any of the four. Just don't let the drilling influance your choice.