Share 'How low can I go? clincher pressures'

Being relatively new to cross and racing in a league with only six events per year, I know I've been over cautious with tyre pressures. So not wanting to risk a flat I've been racing on 70PSI (and it shows). However we have had a very dry season and I'm already feeling battered. I'm about 12 stone and running Conti Speed Kings, based on this what would you put in?