I built the Unifence cove cutting jig shown in the link below.
To use, set the saw blade at the height of the cove to be cut. Bring
the parallelogram jig (shown over the blade in the photo) to the
forward and rear blade edge. Adjust the angle of the Unifence cove
cutting jig to match the long side of the parallelogram. Adjust the
Unifence position to hold the wood where the cove is to be cut (no
angle changes required after initial setting). Set the blade at about
1/16 inch projection and start cutting the cove, adjusting the saw
upward until the cove is complete. The cove roughness was easily
removed in about a minute with a ROS or a gooseneck scraper. Once the
angle is set, all you have to do is move the fence as you normally
would to adjust for different wood widths or postions you want a cove
to be cut.
I tried clamping a fence to the tablesaw to cut coves. It works, but
it is no fun setting up and you have to add small wood spacers to
provide a surface for the clamps to grip the bottom of the saw. You
have to finess the clamp position and the jig angle. This it is not
necessary with the simple jig I made.