Hilla, you ever had a bespoke shirt made? It seems this would be a great instance of "ask your tailor." FWIW I don't have any special cuff design on my shirts and they are neither too wide nor too narrow because they are measured for my wrist. Granted, I always add 0.5" to my left wrist for watch space, but that doesn't affect the basic barrel design.
I have not, I'm in the process of trying to figure out who I want to start with. I thought I knew who I wanted but the minimum order prevented me from being able to try them (quoted me 6 and I scoffed, naturally). So, you're right in your assumption that I'm kinda speaking with limited knowledge here. With that being said, I do know what I like.
Shirt cuffs are normally cut straight. To get the conical shape you need to cut them on a curve, which is why the stripes on the cuff in the OP's photo are wonky.