Humidity on lockdown without a hydrometer

[AtlantisPeeps]

I am on day 17 with my eggs in a LG stil air incubator. I keep the temp within 99.5 and 102 degrees Fahrenheit. I do not have a hydrometer so I just use the three water trays in the bottom and keep them full. The air cells look fantastic and all the embryos are alive and moving. I'm just wondering about lockdown. Should I put two sponges in there? Should they be wet, or damp? Should I use one square of paper towel? Two squares? Wet or damp?

I just want to make sure that the babies don't get shrink wrapped from being too dry or drown from being too humid.

Buying a hydrometer is out of the question, so I'll have to make due.

 

[ChickenCanoe]

All you can do is get the humidity as high as possible. If the windows get condensation, it is a bit high.
Fill all reservoirs and if you have room, add a water container with a sponge. Paper towels dry out too fast.
Humidity is all about surface area rather than volume.

 

[RanchRodeo]

I keep my water pan full and do not have a problem. I have to full daily.