Sorry I wasn't clear
In creating books for my PRS505 I try to eliminate all web references, since it can't reach out to the web. That was why I was suggesting using the second, but changing it to utf-8. But it probably doesn't make any difference since I don't think it actually go to the web to access the encoding. It was more a general idea about creating all purpose epubs than a remark about his particular case since his device is web connected anyway so doing as you suggest solves his problem.