Good and bad news all in one! Glad its fixed, now I know the work ahead of me..
Although it wouldn't hurt to have an adjustable pivot on hand, this is not necessarily how yours will turn out. This is not a common thing and just because it happened on his setup doesn't mean it will happen to yours, but it can happen.
The aftermarket manufacturers strive to make their parts fit into the bellhousing the same way as the stockers do. Sometimes it doesn't work out that way, especially if you mix and match parts from different suppliers/vendors/manufacturers.
It doesn't help that in the Mustang clutch setup there is virtually no room for error. A few thousandths extra here and there can end up in a situation that would necessitate modifications like the original poster.