Here is some stuff I was putting together, for someone else, that may be of some use to you. Here goes...
Here is one of many site talking about wheel offset.
The offset on Mustangs has been in the range of 35-50mm for the past 20 years. For example my V6 perf pack came with 19"x8.5" wheels with 50mm offset.
Although the offset determines the location of the wheel/tire assembly within the wheel well, the actual clearance between the Brembo brakes and the spokes of the wheel is more a function of the wheel design.
The relationship between the car's mounting hub and the edge of the brake calipers is a fixed dimension based on the cars design and the type of brakes. So the clearance required within a wheel is based on the relationship of the wheels mounting hub and the spokes of the wheel.(This distance is not a published figure.) The offset doesn't necessarily change this relationship.
What is required is a wheel designed with its spokes located to allow more clearance to the brakes. Alternately a small spacer could be used to push the entire wheel further away from the brakes. Spacers a frown upon by many and typically recommended to be kept to a minimum.
Increasing the offset of a wheel will push the wheel into the wheel well while decreasing the offset will push it towards the street side.(This may be hard for some to visualize.)
Amount of change in offset, as it impacts the manufacturers design location of the centerline of the wheel, should be kept to a minimum.
The following is a link to a site that shows and compares an existing wheel/tire setup vs. a proposed change. It plainly shows how a change in offset effects the wheels location.
Online Wheel and Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit
Found the following on another Mustang forum, as wheels that fit Brembo brakes. Don't really know how accurate it is.
All wheels on the Brembo equipped Cobras work, the Track Pack wheels from FRPP, the SVT
wheels from FRPP work, the FR500 style work, Steeda Spyders.
The vendors selling the wheels should be able to tell you if they will clear Brembo brakes.