I've had two singleton pregnancies from two clomid cycles - DD is 13 months and I'm currently 10 weeks pregnant. Both of mine were 50mg starting day 5. I'm not sure why the range of protocols but I guess maybe its similar to IVF that the one regime doesn't work for everyone. If your FS does ultrasound monitoring that should reduce the risk of multiples as if you have too many follicles developing they may advise you to abort the cycle. A lot of the multiple pregs in the past were when unmonitored cycles were common. With my second cycle I had to use a hcg trigger as if I'd gone any longer before ovulation there would have been multiple dominant follicles.