I have a question about Yasso 800s - who does them?

This is a new workout for me. I know Yasso himself says start with four and work up to 10. But just this week I did four mile repeats at about 0:15/mile slower than my target Yasso 800 pace. So should I still start with four half miles? Some number between four and eight? Or just do as many as I can maintain the pace, my first time around?

(Don't worry, not doing them today. In fact I get the day off today ... Santa Claus brought me a spa day. )