Hi Ian
You're mad. I bet that has made no difference to your deliberations at all because once an idea like this enters our heads we can't shake it. I have been fondly watching adverts for CZs of the 1970s as other than a brief ownership of a Tiger Cub they were my starter bikes. I, like you, know they would be awful by the standards of the more modern machinery I ride but for a nostalgic laugh I might be tempted.
I suspect price may be the determining factor; exactly how much is a bout of nostalgia worth to you Ian? I know for me £1295 would be way too much, but hey ho you may value your youth higher in which case it might be silly grin time.
Ian