Congratulations. The first hatch is real exciting.
With them hatching a bit late, it means your incubator is probably running just a hair cold. You can try adjusting it if you really want to, but I think I'd try one more hatch at least before I changed anything just to see if the results are consistent. Sounds like you got that homemade incubator pretty close. I'd be real careful adjusting one that is working.