Let me focus the question a bit differently. It's not about how many you run on a single side, but rather if you run them on both sides. The only way I can think that it makes a difference to run on both sides is if you are floating down the river and need to un-flip while moving and need to know that any side you are on you can grab a flip line. That being said, my raft, fully loading is going to need to be controlled before any un-flippin would be done.
“We steer the boat, we don’t alter the river.”