The white light shield works extremely well once you get the hang of it. About 10 or so years ago when I first started this technique, I had trouble envisioning it and it took most of my energy to do it. After a few months, it was really easy and everything was working well.
Others have no trouble with this right off the bat.
Now, I have these protective shields up around my home, my kids, myself, my cars, and everyone that is close to me. It takes very little energy out of me now to do this. It used to make me really tired.
Like I said before, it's all about focus.
Good luck!