How close to 100% RH is close enough? (for corn eggs)

[MouseKilla]

I don't even have the eggs yet but I'm working on the egg box while I still have time to piss around with it. I've got 3" of moist perlite in a Rubbermaid (no holes). I am using the ambient temperature of my snake room (80 - 84F) for heat. The temps are pretty stable in the box so I'm not too worried about that.

The thing I'm not sure about is that the humidity gets up to about 90% but that's it. Everything I've read and heard says to get 100% but I'm not sure how literally I need to take that.

I know some people are more hung up on having extremely stable and accurate temps while others insist that staying within an acceptable range is all that's necessary. I wonder if there is a similar situation when it comes to humidity.

I guess my question is if 90% is high enough or whether I need to up it somehow?