I'm waiting until the day before the next lot of games, injuries in the internationals and all that
Wildcard is active for the entire gameweek, so if you activated it now you can make unlimited free transfers up to 14th Sep
While true it's always best to wait so you change them as late as you can because you notice any injuries then.
I can use the wildcard now and transfer any players injured in the internationals later if I want, up til the next matchday deadline.