I am almost abidextrous and I practiced wrapping gauze one handed with either hand. One of the tricks is to fixate the roll in a way that will allow you to reach around and change grip, e. g. pinch it in the ellbow or hand. It is a knack thing.
A mirror is a good idea. I usually have one in some pocket. Adding one to the FAK wont break the bank. I have a sheet intended to replace the glass of side mirrors of vehicles. Dropping such a mirror wont break it. I used my mirror once when I was fly fishing and firmly planted a streamer on a #1 hook in my cheek. I was really glad that I joined the barbless community way before this event. Hemostats help a lot with the extraction too.