To avoid hitting Nightmares 8, you need to have no more than 1 CP of Nightmares (1 level flat) and just one piece of Nightmares-reducing gear. Due to the <a href="/wiki/Menaces_(Guide)#Menace_Equipment" title="Menaces (Guide)">way the calculations work</a> (see chart), you will see a 2CP reduction no matter how many pieces you have on.

I tested this thrice to check (RIP all those talkative rats sacrificed), and it was always 34 CP gain.