Hi Struthie, this personal experience may or may not be of any help, but....
I had 6 actual IUIs in total (i.e. 6 cylces that got as far as insemination). I was successful on the 6th cycle, which was a completely natural cycle (no stims or ovulation inducing drugs, unlike most of the previous cycles).
I'm sure my actions were completely unnecessary, but as the time of ovulation approached, I tested twice a day for the surge, so that I could more acurately pinpoint when the surge actually started (I managed to miss it once and ovulated and the IUI was cancelled - so really wanted to get a better handle on it for my own sanity!).
I detected a faint surge in the evening, and rang the clinic the next morning (the ov kit showed a stronger indication in the morning). I was booked in for an early IUI the following morning. After the IUI I spent the rest of the day in bed with a pillow parked under my backside - probably unnecessary too, but it made me feel like I was doing something useful.
I remember feeling that the timing made sense to me, whereas on previous cycles, the timing didn't make a lot of sense to me (but then again, I'm no expert!). As test day approached, I felt pre-menstrual so assumed it hadn't worked, but on test day, I was amazed and shocked to see a faint line appear. Unfortunately I miscarried at 6/7 weeks and have since gone on to IVF.
Infact I tested negative today (2nd IVF - did unofficial test, will do official test on Friday - thought I'd let myself down gently), and feeling at a loss about whether IVF will ever work for us, and now feeling tempted to go back to natural IUI as at least I conceived with it in the end. I'm sure this feeling will pass.
Good luck with your next cycle.
Georgie
I think you are right to be concerned with the timing of basting. Everything you read and hear appears to suggest that it is better to have the 
there before ovulation. This makes sense as we know that they live for a longer period of time than the egg. Do raise it with the clinic and see what they say.
