Tyre Pressures for Slicks?

[Nafe]

A friend recently purchased some slicks for his MY00 WRX for some circuit work. But as neither of us has run slicks before, we have no idea what tyre pressures they should be set at.
I'm assuming there's an optimum pressure for them to be at when hot.....

Tyres are 225/600/16 Pirelli PZero slicks on standard MY99 rims.

Any help would be appreciated :)

[Nafe]

Its an MY00 WRX - stock springs and shocks
The only mods are Whiteline/MRT Swaybars and Anti-lift kit, MRT Sports pads and AP Racing brake fluid.

All other suspension settings are standard.

The car won't be flogged too hard as it will be the driver's first time on the track, but I expect it to be driven say 75% of it's limits.

I won't have access to a tyre pyrometer, so it's going to be the old-fashioned hand on the tyre trick.

I know our Yokohama A032Rs are supposed to run about 36psi when hot, but I wasn't sure with the slicks.