Yes I am in the process of sponsoring her...
. I've passed the first stage (sponsor's assessment), now still going through stage 2 (sponsored person's assessment)
Oh no worries....the free/regular Skype is absolutely fine.....and yes just get screenshots....no need to overdo them (just get some every few days, and do this regularly)......I'd take screenshots of the chats, as well as the video call sessions (i.e.: showing both of your faces).
I also used this free program to extract and import the text chat logs from Skype....a really neat program which I think you should download and use too later
http://www.nirsoft.net/utils/skype_log_view.html