I'm building a printer that has a 326x326x6 mm aluminium bed. While testing the bed heater, I realized that the thermistor is at target temperature way before the whole aluminium bed is. Eventually (like 10 mins latter) the whole bed is indeed at temp but by then Marlin will be on the 5th layer or so. Surely I'm not the first to confront this issue, so any pointers to how others handle this ? Thanks.