My DD, who will be two on the 20th, has had two, and will have her third in August. She had a UTI when she was 2 months old, hospitalized for a week, and then diagnosed by VCUG with Vesicoureteral Reflux a month later. She has had only a few repeat UTI"S since, but is on daily antibiotics. Since you have done some reading on it, you will understand when I say she started off at a Level 3 on both sides and last August was at a 2 and a "strong 1." She is outgrowing it, so hopefully this next VCUG will be the last.
There is no nice way to put this, but the VCUG is pure hell! As I am sure you have had catheters, you can begin to imagion the discomfort for the kids. She will get the cath and they do a live x-ray as they watch the dye flow through the urinary tract. I was able to see my daughters reflux the first time with no problem. The hardest part for me is having to hold her still as I can for the test. I hate to hold her there as she cries, not being able to pick her up. The second time was worse, as she was older. I think the hardest part for your DD will be that she has to void on the table before she can get up, at least that is how it is supposed to be done.
I have done a lot of reading on Vesicoureteral Reflux and the VCUG's, I'll be glad to help you out in any way I can. When is your daughter's test? I will keep both of you in my prayers!