Idea for a Shelly, but which one?

I came up with this idea last night to use a Shelly to monitor the power on an old washer and an old dryer. When the power draw on the outlet drops from let’s say over 300w to below 100w, it can make a light flash or change color to indicate the load is done. I would adjust range but I know the dryer can cycle heat on and off with motor still running and none of these appliances every draw 0W, so I would want to account for phantom draw as well.

My question is if this is best done with a Shelly PM or a Shelly EM? Has anyone tried this before with varying luck?