I had all mine qualifying within 2 weeks and racing at 3 weeks if they were in full work when they left Australia - they never got sick. However, I got a lot of "tut tut" from the USA trainers for not giving them 1-2 weeks off on arrival, which does appear to be the done thing. I find keeping them on sulfa/trimethoprim during the duration of their travel and also the first week they are in the country, 2 days off after they arrive at the farm in NJ, bute every day for 5-6 days in a row after arrive at the farm in NJ gets rid of all their travel aches and pains and by the 4-5th day they are feeling GOOD!
I did 3 shipments and the horses didn't get sick once. I had one horse get sick for a week, but he had already been in North America for 12 months so you can't count that Noel is a fantastic trainer and has had a number of overseas horses so I am sure your mare will be fine she is in GREAT hands My 2 week qualifer - 3 week til racing is about as quick as you can get them to the races over there. A lot of trainers take 4-6 weeks.... I can't really tell you how long they take to settle in since I did things differently