There are 3 different kinds of Clays powder. Plain clays, international clays and universal clays. I listed them from fastest to slowest (titegroup falls between clays and international clays). The clays most people use in 45 is plain clays and in my opinion is the best as far as how it makes my gun recoil. Using plain clays in 40 is not recomended. The reason being huge pressure spikes on your way to major. However, I know of several people who use plain clays with a 180 in 40 with great success. The reason they can do this is that they load long (1.22 or longer) giving 40 a slightly larger case volume. I have been using titegroup for for my 40 loads for a long time and have shot my friends clays loads and the difference to me is very slight and not worth the risk of a pressure spike.
Anyway, if you have been loading universal clays in your wifes 45, I think she would be pleased with plain clays. The recoil seems much less to me.