Ok I'm going to say something that might get me in trouble... 'vintage' is not always what is best. Thrones are something that require a little consideration. We're talking about the future health of your spine if the throne is not right.
Round thrones cut off free blood flow to the legs and press on nerves in a spot behind the thigh that guarantees you'll be sore after sitting on it for extended sessions. Ergonomics behind the kit dictate that your legs are free to move unencumbered. For that you need to look at bicycle seat style thrones!
Think of your leg movements on a bike, they can move freely without the nerves being pinched or the blood flow to the legs being cut off. You ever get tingling/pins and needles in your legs after a long gig? The nerves have fallen asleep... round seat! Most vintage thrones are round seats. As a friend, I'm telling you be good to your body. Get an ergonomically shaped bicycle style drum seat like a Rock N Sock. You'll be glad you did the first time you play a three, or four hour gig.
Dude the main consideration is not looks, or whether it completes a vintage kit, or whether it matches the rest of the hardware. As a drummer you need to be well-anchored on the seat. Your torso needs to be centered on the throne so when you need to lean into the kit to put your body in between two targets you don't lose your balance. Go with a bicycle seat. In this case screw vintage, make life easier on the 'modern' drummer!
John