I just need to say it DOES happen that clomid can give a false positive opk result. That is absolutely correct. HOWEVER if you leave 3-4 days between last dose and using opk's you should avoid this.

Clomid does not always give you a cd14 ovulation. On 150mgs of clomid I ovulated on cd20. I conceived Imogen on this cycle. Our bodies are individual and will respond differently so what response my body has may not be your experience. There is a very wide variation of normal. For me it didn't matter what days I took the clomid my cycle length was still long. I had a trigger shot with Immy and my follie (the largest) was 28mm.

Fertility clinics usually give you opk's when you have your follie scan.