I was excited about this build and tested out a few times. I have the same issue with clockwork, I run out of energy too quick. This only helps when you are either are only sniping or controlling yourself with farming. At the stage you suggest to get clockwork you still need to be heavily farming to have a chance to do the full build and stay above the other team. Have you tried clockwork as your third item instead? A video of you playing would be handy to see how you actually play with...