HELP! IUI quesiton

I am on letrozole CD 3-7. Just finished yesterday so I am on CD 8 now. We were planning timed intercourse with trigger shot this cycle, but I’d like to switch to

<a href="https://glowing.com/glow-fertility-program">IUI</a> if possible. I called the RE but they were not very helpful. They said just come in on Friday for my scan as usual to check follicles and doctor will tell me if we can do

<a href="https://glowing.com/glow-fertility-program">IUI</a> then. They are closed Saturday and Sunday. If we decide to do

<a href="https://glowing.com/glow-fertility-program">IUI</a> on Friday will it be too late to get the sample ready?? I ovulate on my Own around CD 14, so I can only assume my follicles will be close to ready over the weekend. Should I push for a scan on Thursday Instead? Help!