I have a variety of tyres on my bikes, including Duros, Bridgestones, Metzeler, Mitas and Dunlop.....
I cant fault any of them for wear and grip, well Im maybe not happy about the Bridgestone on my CB750.......
My 1977 RD200DX has Duros on it because it was the only tyre available in the miniscule sizes spec'd. It works great at the somewhat-less-than-warp speed the bike is normally ridden at. And it looks period correct.
My 1971 CB750 has Bridgestones on it and I noticed yesterday that the sidewall on the front tyre is cracked with only about 2000 miles on the clock [3 years old] so Im going to new K70's for it most definitely.
My CBX has Meztelers only because they were available when I needed them, but they look somewhat correct for 1979 and wear and perform great.
My BMW R1200ST has Bridgestone Battlax tyres and Ive noticed the front is starting to wear in scallops type of wear and Im told this is somewhat typical of BMW's, but it has worn well and hangs on well past the point where my skillset ends, so Ill probably just replace it with another BS.
OPINION: If I was using my bike lots and 'vintage' appearance was important then Id throw K70's on it, otherwise Id look for a cheaper tyre that looked correct.
Al