Hi Derek,
Whatever you do don't go by the 1950/60's figures because they use different compounds for the tyres these days.
The following figures will probably seem a bit high to you but they have worked for me after low pressures caused tyre creep and regularly pulled out valves. Experimenting with slight increases of pressures over the years has resulted in me using 26lb front and 32lb rear for normal use. If I carry a pillion passenger or if I'm loaded up with camping gear I increase this to 30lb front and 36lb rear.
I tend to do more long distance work more than local running and I don't see any noticeable central tyre wear that would suggest that these pressures are too high. I seem to get a comfortable ride too.
Beezageezauk.
