Hi,thats another big benefit of the LED they don't get hot at all.
I don't think candling them again will harm them,but I usually only candle mine once or maybe twice.On day nine there is no mistaking then weather or not an egg is fertile,I then throw out all the clear ones.
I sometimes candle again on day 18.
I didn't used to candle at all until I had a bad goose egg explode in the incy,what a mess.
Graham.