very rewarding to fit your own tires, but then there is balancing- I bought 'old' used hubs for my VW bus and my wife's Honda on ebay- spacers fitted for use on my pendulum (motorcycle type) balancer- I took 300g off each Honda wheel and added around 30g ! ! ; )

Those OZ wheels are notoriously soft. I found that a quick trip to Italy and some of their back roads soon knocked a square one back into shape ;) Well done with the horn. On the later cars, where the compressor is in the light pod and the horns in front of the rad., you can get a modern nautilus horn into the pod. Of course, that means that the noise comes from one corner of the car, rather than the middle - but it's a cheap and easy fix and only the most anal of concours judges would notice.

Tye Age - Generally in a box, like 0208 would be 2nd week of 2008. Or 1515 would be 15th week of 2015. But tyre ages over 20 yrs may have nothing, as nothing was normal back then.