For portrait work, flying solo is nothing new or unheard of for me. Weddings, however, I trust a second photographer to do their part. Fortunately for me, my wife is my co-photographer. She primarily runs her 60D and 35L for the majority of every wedding, this allows me to switch between the 17-40L and 70-200 2.8ii. This set up is simple and gives us great results.
Our last wedding was in a lodge on a very rainy night. I rented the 50 1.2L and 24-70ii both of which I've considered buying. The 24-70ii was AMAZING, but darn expensive, so we're going to wait just a little bit before pulling the trigger on that one. One thing we learned though, we both needed a flash, it seems obvious looking back, (hindsight's 20/20), but I was hoping the 50L at 1.2 on a 5Dii would absorb enough light, which was true for the most part, however, a flash on my body would have made my life so much easier. Within a week, I bought the 600EX-RT. It was a lesson learned the hard way for me, and if I can help out any other forum member by sharing my experience then it gives me the warm fuzzies and I know others will help me with future insight. The image below was shot w/o a flash, 5Dii, 50mm, f/1.2, iso 4,000 and 1/160, so it was still capable of performing when tested.
As for the method to our madness; my wife is incredibly personable and works tremendously well with the brides. I can fairly quickly become friends with the groom and groomsmen. I trust that she takes care of business and likewise, she feels the same for me. I spend the majority of my time, pre-ceremony, following the groom with the exception of spending time, taking ring shots, wedding dress pics, makeup, etc. From the ceremony onward, the bride is our major focus. If things are slow, we attempt to get portraits of every person who came to the wedding, focusing on the oldest and the youngest.
I think anyone could write a book on what they have learned from their first, second, and third wedding. If I can help you or anyone else, feel free to PM me or shoot me an email. It's my way of paying it forward, for those who have helped me in the beginning.