Hi eveyrone,
Will do my best to answer your concerns. I have an LG so what ever I suggest , see if you can adapt it to your incubator design.
2-4 small jars filled with warm water, and have a sponge, I cut them to fit, sticking into the water jar like a straw, with the top hanging out. THe more the sponge is exposed to the air , the more moisture is wicked from the jar into the air.
I also lay wet sponges in my homemade incubator to get the RH up quickly. Or use rolled paper towels that are high quality paper towels that hold their shape when wet.
Some incubator designs need the water replenished regularly. Either use a straw thru a hole to keep replenished or similar idea.
Other ideas that I have read: lay a wet paper towel on the floor and put eggs on top, dribble in water to keep paper towel wet.