I have a Canon Speedlite 580ex and a Canon Speedlite 430ex. Normally, I put the 580ex on the hot shoe and set it to master, and put the 430ex on a tripod off to the side set to slave. This works OK in portrait/engagement photo shoot situations where I have time to ensure that the 430ex has line-of-site to the 580ex's sync flash. The problem comes when I'm trying to shoot weddings; things happen at a very high pace and I'm usually moving around a lot. It's impossible to trigger a slave flash reliably during any part of a wedding because of how much moving around there is. I need to upgrade my flash system. The first thing I need is to switch to radio sync so that I don't need direct line-of-site to the slave. One of the things that I really like with the Speedlites is the ability to quickly dial in a ratio of flash power so that the slave or master can output much more power than the other. Are there any solutions that allow me to keep a hot shoe flash while also supporting the ability to specify master/slave/group output ratios? Is there another solution I should look for? Should I ditch the speedlites and switch to a fully third party lighting system? The requirements/parameters are that I rarely have reliable access to electric outlets and the system has to be pretty portable and work both indoors and outdoors in a huge variety of shooting situations. Thoughts? Thanks!