Adam,
Can't speak for the .45, but my .54 Hawken takes a .530 ball and a .010 patch; if I were to take and try these ITX balls,
.540-.524= .016.
While it wouldn't be a 'perfect' fit, I think a .015 patch might fill the bill, and those are easy to find.
....Let's hope we never are forced to find out!
Also, I'm wondering since they are denser than lead, if they are a bit undersized to make the wieghts match closer? Just a thought......