Greg Black 4.5G-5G and GB New York 5.5

[Tjamboricua]

I currently own a GB 4.5G-5G Regular weight Trombone mouthpiece and I am interested on a GB New York 5,5 trombone mouthpiece. According to Greg Black's website both of these mouthpieces are similar with regards to the rim width and cup depth. Are there any other differences and how the New York Series compare to the Standard Greg Black series?

[modelerdc]

I once owned a 5.5 and a 4G both by Greg Black, very close in size and depth of cup. The Rim on the 5.5 had a different feel, with a curvature that gripped a little better. The 5.5 had a slightly different throat-back bore which gave it a little more focus than the 4G