How do you decide to go right or left first?

I've been doing a lot of research on this, listening to some great trainers, etc. Most all say that if your horse is stiffer on one side, that should be the side they turn for 1st. To get in and out faster, and use their softer more bendy side for 2nd and 3rd.

Thoughts? 

I've heard dominant lead for two turns. 

I had a horse that took over a year to be able to carry herself correctly to the left. The trainer knew she just needed time to strengthen, that it wasn't a lameness or conformation issue, so he started her on the pattern to the left. Now that she is equally good at loping to the left and right she has become a really good lefty. 

Logic would say that but then there are people that believe that you should go with their dominant side first, because that is the money barrel that sets up the whole run. I see the logic in that also, so I say go with whetever works for you.

Just like humans, horses have a dominant side, if they are running in the pasture or pen, what lead are they on most of the time, what lead do they chose to run on when not being asked. If it's the right lead take em to the left first and vice versa.