Preheating all the way through is definitely good! An old rule of thumb I’ve heard is a skillet is preheated properly when the base of the handle is too hot to touch.There you go makin me hungry again! Made my eggs yesterday morning in the little pan you supplied. Think I should have let it heat up a bit more before adding the butter and eggs. I have the #5 and a 10.25" here at the house. At the cabin I have a 12" and a rectangular griddle.
Enjoy the iron and let me know if you need anything else.