IG
100 people is a lot to roster by hand so an IT solution would be useful not to mention cost effective. I have not tried any of the following but they may be helpful:
http://www.infographics.co.uk/soluti...tency/rota.htm
http://www.rostering.co.uk/ Let me know how you get on and what you end up with.
Good luck.
Rgds
EM