To get an even coating on your edges, you may need to scoop some epoxy off the floor with a metal spatula or spoon and dump it back on the edge. Do this as often as necessary to get a smooth covering.
Also, keep in mind that the pennies on the edges will prevent the epoxy there from being glass smooth. My desk has a slightly ripply effect to the front edge, which I actually think feels really cool. Just be sure that the epoxy gets in all the cracks, and that you don't miss any areas.