The idea of double TIleType ( the default one) is to be twice the size of a single one, the quadruple type is for times bigger than the single. This is by design.
You can modify the size of a single tile size (its height and width) and double and quadruple respectively by setting TilePlaceholderISide
property of RadTileList. It will not change the width of the column, but rather the single side of a tile. However, it might result in a view more close to what you require.
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