Yamaha Mouthpiece Trumpet 14D4

So I've been playinga 7c for 8 years or so, I can go pretty high ever with a 7c (High F) . This has one of the most beatuful tones I've heard, everything from low F# 2 octaves up sound full and beautiful. Indeed is really hard to go high, I hit a High D but it sounds strangled for now, I only had it for a few days I still try to get used to it. I feel its harder to blow but as long as you find the sweet spot for breath youre good to go. I play it on a 1967 Reynold Cleveland Ohio and it works really well. It would be around 5c with a b cup, also I urge you to read the threads on this mouthpiece from trumpetherald, it helped me to understand what I should expect.