Yep - I was terrified when I heard it was twins, but it is seriously the best thing ever. I am so happy.
Have you decided on medicated or non-medicated IUI? I had two rounds of non-medicated first (against their advice, but I had never tried to conceive before so thought I might just be lucky and v fertile, plus I was worried about "risk" of twins with medicated - hah!). If I remember rightly there was no scanning at all with that, just peed on the stick and called them the day I got the hormone surge, then went in the next day for insemination. I decided after 2 goes to stop doing this as it seemed so utterly random and I had no idea what was going on with my eggs.
Then I went to medicated cycles - I can't remember the exact times they scanned, but it was a lot more controlled and they knew exactly what was going on with the eggs, so don't worry about that. I think it was a few days into the cycle, they'd measure them and tell you to come back in x days, depending how big they were and would check again. When they were the right size they gave me an injection to stimulate the release of the eggs and then I went back in for treatment. I was still peeing on the sticks, but I think as they were the right size they simulated the egg release rather than waiting for it to happen or they would have got too big.
I used the ovulation sticks with the smiley faces, clearblue I think? I didn't want any room for getting a wrong reading, I figured if you're already paying that amount you don't want to bugger things up by getting something cheap that doesn't work.
Re LWC - it's hard to comment really, as I didn't visit any other clinics, so have no point of comparison. I guess they weren't particularly warm and fluffy, all very matter of fact. The receptionist was nice, but I didn't feel a lot of warmth from the others, not that it was a problem. For me the main thing was the attached sperm bank - I couldn't face the extra stress of having to get sperm delivered at the right time and stuff, you just chose the sperm and it was there when you needed it, no hassles. And also I could get there in 20 mins from work, so I just made up meetings and popped off there and back during the working day. That was more important than anything else really, as it made it do-able. And at the end of the day they made it work - so no complaints! I'm not sure about whether they charge you for the sperm, I think perhaps they do, but you'd have to ask them. I'm not sure why you'd have a cancelled cycle with IUI though, assuming that you know you can ovulate and they are monitoring you?
Sorry - mega post!