Thanks for your query.
I read your query and understand your concerns.
Following is my reply:
1) It takes 36 hours for ovum to rupture. I think you time your IUI 36 hours after trigger.
2) Single IUI after 36 hours of trigger is good enough.
3) Next day scan might reveal a ruptured follicle.
I hope I answered your query.
I will be available for any followup queries you have.
IVF & Infertility