This makes me really glad you found your way here. Whoever told you this, please do not take any advise from them ever again on anything ever. The only difference between feeding rats or mice is the quantity you will need to feed when they are older and larger. I have a couple 1200ish gram snakes that have never has a rat in their life. They eat between 3 to 9 mice every week.
You want to get the surface temps not hotter than about 95 degrees.