A few things I learned doing the 1 hr Postal swim last night

At the last minute, I decided to skip the normal workout and do the swim. I get going and I have a lane mate who I'm pretty much side by side with for the first few hundred yards until she broke away. What was interesting was this. Her turns were a little faster. We were both doing open turns, but she seemed to gain half a length on me coming out of each one. If I breathed bilaterally, I'd gain on her. I'd also gain on her if I breathed on the left (right is my normal side). But whenever I'd breath on the right, my pace would slow. The problem is that if I breath on the left I get side stitches. If I breath bilaterally, I can start to get them but not as bad. My questions are first and foremost, how do I use this information? Do I try to breath bilaterally more? Should that become the way I swim if I'm faster that way? Would I ever want to do an open water swim breathing bilaterally. I can do flip turns. But they're not very good. I generally don't use them in distance because I seem to get tapped out. Since I never plan to race in a pool, I generally haven't worked on them much. Is there a technique for a fast open turn? Or should I do more flip turns? Finally, would biking 30 miles that day affect how well I did in the hour swim that evening?