There is no “correct” pressure, it it very much how the tyres feel to you, what your driving style is and everything else.
However as a starting point, 27 to 28. See how it goes from there, if they feel stodgy, then more pressure and bouncy and snappy, then less.
You will likely only be doing sessions so only 10 minutes before each chequered flag so not really enough time for overheating to set in.