My bitch is 18.5 tts,she is very quick,has great stamina,can turn like she's on rails,but on uneven ground at night she struggles,and thats because she can't see the quarry.
Put two marks on a stick,one at 19 inches and another at 24-25.Crouch down and place your eyes next to the first mark and then the second,you'd be amazed at the difference.