You want to make sure you are using a cool mist humidifer, I guess that is the best kind. As for the brand I can not remember what kind I have, but it does have a big resovior. I can sometimes get through two nights with out filling up. Using the saline drops and the nose sucker are the only things to do for them when they are this age to help clear the nose. You can also elevate the mattress by placing some towels underneath it this will help them a little. Or sleeping in the car seat for when they are having trouble breathing when laying flat.
As for temping, unfortunately taking a rectal temp is the only accurate way to get the core temp. I think the suggestions the other posters gave you for positioning is the best option and using a "speed read" makes it go quickly.
Good luck, I know it sucks to watch them like this,
A.