My digital thermometer has a probe which I put in the container, then close the lid. Make sure you are not using guages when measuring an incubator temp, since they are not accurate.
yup! digital thermometer is the way to go. I suggest having a sample container with the probe inside with everything a normal container would have except eggs and just put the probe inside and you wont have to worry about air going in if a whole is left from the thickness of the probe wire. I dont worry about the humidity because that wont really be reliable. just moisten the substrate as its soposto and dont open the containers to much that a bunch of the moisture will get out. The air will be saturated with water in the container and when you open it it releases that air and the water in the substrate will evaporate to saturate the air again until it runs out of water which takes a lot of opening of the containers or unless you punch unnecessary holes in the container. Hope I dint go of topic to much and you understand what I am saying.....
Nope just one probe for the whole incubator. I put the "Test" in the middle of all the container and so If you incubator is like a hovabator it should be ok with just one. It doesnt really matter were the probe is in the container but I guess if you want to simulate the eggs just put it in about half and inch (1/2)