I wear Salomon Syanpses which have a smooth round toe.... Union toe cap just doesn't work with it. Too bad cause outside the toe cap I like the Unions.
Yea, some boots just won't work with those open toe cap designs. For those boots you would want to look into bindings that have some kind of stretchy toe cap, like the Rome and Ride binders.
Or you can Frankenbinder it:
Frankenbindings: Toe straps/caps! | Jibby Snowboarding