I love left and right turn, but commercial guests often don't get it, and when you have them for a half day, directionals are often optimal. I tried it today on a competent crew, and, "Left side back, right side forward!" was way more effective than "Left turn!"
Only guide from one side is a big mistake.
First, muscles. A season from the right only leads to less seasons in a lifetime.
Second, injury potential. I nearly blew my right knee on the Lower Kern in 2005. I couldn't quit, and I couldn't guide from the right. I wished then I was more comfortable guiding from the left.
Third, optimization: Most of our draws are stronger than our prys. Often we find ourselves prying from the right too much. One of my rookies this year found it easier to guide the Blue from his off (left) side due to the nature of the rapids. I think he's right. I should guide the Blue more from the left.
ARTA sounds awesome!