With mail ordered eggs allow them to settle fat end up for a day at room temperature before putting in incubator. Using water bottles for a heat mass is an excellent idea. Put them in now and you'll see your temps even more stable. Also don't panic when the eggs are first put in incubator, it will read low for hours until they are up to temp. The time to get up to temp depends on how many eggs you set. With two dozen it can take overnight. With seven maybe just a few hours, regardless, trust your settings prior to setting eggs and don't make adjustments until 12 hours has passed or you'll be chasing the temp all around.
Just got home. water bottles seem to help, I just needed to adjust the temp. I put another one in. Seems to be working. Thanks!