I had my iui done at 24 hours.
I think his boys can survive at least 48 hours, which is longer than the egg would, so I reckon you've probably got it covered..
I had mine done at 10 and 38 hours. What's most important is that they hit your ovulation time... and that differs between women with or without the boost shot.
My first IUI worked. The only thing left for you to do, unfortunately, is wait and think positive thoughts. I know, easier said than done. :)
Good luck and lots of sticky baby dust!!!!
Thank you for sharing your stories - keeping my fingers crossed! :)