Unfortunately, what you are looking for does not lend itself to a one-man band. Anything large enough to cover more than a close up face shot requires a huge overhead frame and silk with very sturdy support. Any wind and you'll quickly discover some sailing lessons. These rigs take a lot of time to erect and require a good sized crew to man them.
There is a very simple solution to your problem, however. Just carefully choose your locations and time of day. Low sun falling on the subject's back will solve the squinting problem and give you a beautiful 3/4 backlight. Avoid shooting when the sun is high and overhead and don't shoot with the sun falling on the subject's face and in their eyes.
A small reflector can help you paint the face hotter on one side to add three dimensionally. If you can find a pure white one, a popup automobile sunshade will serve very well at very low cost.