There is no difference in spa cover performance either way. It is simply your preference. A - This is the height of the acrylic lip. This will determine the cover s skirt length. D - Outside dimension of the wood cabinet.
Some covers have rounded corners.
The diagram above shows a rounded corner with imaginary dotted red lines. The length of the red line represents the measurement of the radius corner. The lines start where the cover begins to curve, and end where they cross. If in doubt, a slightly smaller radius will slightly over hang the spa while a larger radius will not cover the spa completely. For advanced rounded-corner measuring tips please click here .