Consult with me on designing email split testing campaigns

One of my clients has asked me to come up with a plan for a few email campaigns that involve testing. I've already spent two hours online trying to figure out what sample size to use for his list and how to proceed, but am at a loss. Looking for someone who can consult with me on the back end to help me design these campaigns properly. Prefer someone who speaks great English and can talk live via Skype or Hangouts this afternoon -- Eastern Daylight Time. I'm looking to talk about sample size and levels of confidence and confidence intervals, or perhaps if sequential testing is better.