With done this many, many times. With this organisation, are you expected to teach and entertain them, or are the students attending a course and taken out on activities with them?
We always found it great fun - but I was very sad to see that some people did it only for the money, and didn't feed or looking after the kids too well. I'm sure you'd do a grand job though.
We are still in touch with some of the students we had to stay with us- even though it was a long time ago, and visited some of their families.
Having two at a time is easier, but some organisations do not accept this as it means kids speak together in their own language.