For seeds that prefer a low temperature to germinate, I don't turn on the controller for the heat mat. For other cool-weather plants I set the heat mat controller at its lowest level of 65 degrees.
I often transplant cool-weather plants, such as spinach, chard, parsley, even cabbages, directly to garden soil, assuming it's ready and a suitable time, and they are hardened off. It takes planning to get these seeds ready when the soil is ready.
However, in some situations with cool-weather plants I repot them in potting medium that I create using the seedling mix as a basis.
In this case I would continue the rest of the procedure for Heat-loving plants.