If you cant find a suitable corner round you could finish the edge of the tile at the front of the curb or finish the front edge corner if you choose to tile the front side of the curb which i recommend with grout.
Shower door curb edge finish.
I do not recommend finishing any tile edge with caulking.
A good shower curb keeps water contained in the shower area preventing you from soaking the bathroom floor.
Once the mesh is in place it is stapled onto the front bottom edge of the curb and you float the 2 to 3 inch thick layer of finish mud that forms the shower pan which locks the inside section of.
A great and well made shower curb does all that and is fully waterproof.
As you might expect different people use different methods to build shower curbs.
Shower door bottom seal 2 pack glass shower door seal strip shower door seal frameless seal shower door stop shower leaks and create a water barrier 3 8 x 39 2 4 7 out of 5 stars 166 17 88 17.
They can be installed right up to the edge of the shower and need no transition to.