The class I race in in NZ does not restrict me to 'classic' race tyres but I use Dunlop 03G race tyres, with stiff sidewalls and 28psi in the front and 25 in the rear with the inner side pressure 0.5psi lower (depending on circuit rotation) . I'd ask your supplier for a guide to at least start with. Presume you'll have some opportunity to test the car / tyres at another circuit local to you beforehand so you can sort tyre pressures out and scrub the tyres in?
What i will be using will be very different. I'm on Dunlop L section crossply CR65 tyres. I have done some testing at 30 and they were lovely, but weather that can handle 2 hours is another question. They are so much more fun that radial. I ran these before http://www.longstonetyres.co.uk/page/16 ... -tb15.html
they were amazing. The lap times would have been much better, but the crossply tyres are so much more fun.