Right on Tony K.... It took me a few years to get the sound where I believe it's effective for this genre!
You need to beable to cut because of the other things going on around you, loud guitars, bass, drums, keys etc.... Inless you wear in-ear monitors you'll probably blow much harder just to generate a tone that can compete with your surroundings! Your looking to achieve a commercial sound and that kind of combination takes some experimenting! Your Bach 1 1/4 may be difficult to achieve this but some guys can do it! I'm not one of them! If I were you I would contact GR and go through the interview/survey process with them, they do an excellent job!
Having played mostly in these situations I have also found that the blend and tone of the other horns in the section also shape the overall sound. For instance, if your sax player is using a jazz setup creating a darker more mellow tone, that can have at times an almost subliminal effect which will makes you work harder to compensate for his lack of cut!!! I hope I explained this correctly.
I would also suggest listening to a bunch of Ska/R&b/R/R and begin by trying to emulate the trumpets that you hear... look for live recordings if at all possible, I think those will give you a true example of what your trying to achieve in a live situation....
Hopefully this example gives you an idea!
http://www.theburners.com/media/audio/vehicle.MP3
Good luck with yourself!
Tony G