I'd classify Tia as small - 6 pounds - 6 inches tall

Tango is medium - 36 pounds - roughly 18 inches tall (I can't remember exactly at the moment...)

I voted the Dobes as large although some people might say X large:

Keeva - 45 pounds - 21 inches tall (she's underweight though because of who ever had her previously...)

Winston - 80 pounds - 27 inches tall