Magical Thoughts on Angles
This is an important topic in magic that I couldn't resist giving my take on. So here it is. Do angles really play a major role in close up magic? Yes, but I believe that their worrisome nature can be overcome with simpler (not necessarily easier) sleights and spectator management.
In my opinion, there are many sleights and tricks that can be done surrounded. However, some magicians have forgotten our long-lost tool called Misdirection.
Learn to control your audience by saying things like "Come around to the front, so you can see better, " or in a crowded situation, "Could you give me some room, please?" These lines will work wonders. Asking for an angle-proof trick in my mind is the same as asking for a spectator-proof trick. If your audience wants to see your magic, they will listen to what you tell them and respect your simple requests, unwittingly making the entire effect easier for you as the magician.
As far as angle-proof goes, Two Card Monte, ACR, and countless other tricks fall into that category. (I use the above tricks as an example, since the vast majority of magicians have performed those effects). However, I noticed that most of the sleights you mentioned (especially tilt) CAN and HAVE been done surrounded. It's all up to the skills and crowd handling of the performer. I recommend learning a good breakless double lift, and never holding a break for too long. Spectators can and will focus on stationary objects, when not being directed or MISdirected on where to focus.
In closing, don't be afraid of angles. Get comfortable palming and even doing the pass surrounded. And it might also help to remember that you'll never fool ALL of the people ALL of the time...unless you have a TV show. I hope this helped somebody out...