dan, one thing you mentioned that everyone else seems to have missed is that making a connection to the supply side of a domestic single phase meter( i take it this discussion is about single phase? ) is COMPLETELY illegal. I hate sound like a sour puss but why go to the trouble of calculating...
If you don't mind the follow up call from a salesman, then Deta in the UK have a fantastic program that they will despatch on cd to you as an evaluation. There is no time limit and it really works !! don't have their url to hand but it probably was .com or .co.uk
I also understand there is soon...
