Sync smaller data file with larger data file?

[nklaver]

I have been using the sync function on .mac and now mobileme for years. I've just culled my email lists and now the file is much smaller. I need to sync with my other computers, but I'm not sure if the smaller, culled file will supercede the older, larger data files. I'd hate to have to go through and re-edit the email lists. Should I remove my other computers from mobileme, then sync with the new smaller data file, and then add the other computers afterward? Help!😕