The best baling tractor I've used is our Case IH 5140, it's got a powershift and is small enough that's it's really handy but yet heavy enough that the baler and wagon won't push it around.  We used to use our 826 on our 1034 wagon and it seemed to be a good match, dad said it worked alot better than the 706 LP gas he used on it before.  We've got a Hesston 4590 baler that would be about the same capacity as your 575 and if you want to push the baler very hard on anything but level ground I wouldn't put anything smaller than 80hp in front of it and a 100hp tractor would be even better.