i've just built myself a mk2 escort rs2000 with a stage 3 cosworth yb! when fitting it i swapped the exhaust manifold from a 2wd to 4wd, which ment i had to shift actuator

i live about 200 miles from a rolling road, and would like to get a few miles on car before i have it set up, whats a safe (an useable) boost level to set it at till i have it set up on rollers?