You know, I don't think how you run the light cord is a life or death matter. I think there are some advantages to having it on the left. I think wrapping it around your arm on either side is an inconvenience, because if you want to clip it off, you have to unwind it, but it's minor. It's also not a big deal to get a light cord lengthened or shortened, and if you're at all DIYish, you can do it yourself (I have learned how). I also KNOW that it is quite possible to put a light in a temporary hold and then put it back without any disco -- it's called light discipline, and it can be learned. And it should be learned, because if you dive with people who use their lights in a disciplined way, they're very sensitive to erratic light movement (because it can be a sign of diver stress or problems) and it makes them crazy.
I like my light in my left hand, and I run the cord over the long hose. I prefer NOT to make wing adjustments with the light on my hand, so I use a temporary hold, and I don't find it a big deal. I've never had anybody donate gas to me with the light on the right, so I can't comment on whether it blinds you or not, but that would be a good reason not to put the light there. The bottom line is that light cord routing is not a life and death issue, and you can read the arguments people have given for each of the ways of doing it, and decide what seems good to you.
I like my light in my left hand, and I run the cord over the long hose. I prefer NOT to make wing adjustments with the light on my hand, so I use a temporary hold, and I don't find it a big deal. I've never had anybody donate gas to me with the light on the right, so I can't comment on whether it blinds you or not, but that would be a good reason not to put the light there. The bottom line is that light cord routing is not a life and death issue, and you can read the arguments people have given for each of the ways of doing it, and decide what seems good to you.