I believe size wise it goes ATB, GTP, ETB (smallest to largest)
At least with the ETB's locality matters when it comes to size. Most are in the 4-6 ft range but the Basins can get up to 9 feet.
Yea i watched a couple of youtube videos on atb's and they all seem really slender. I love how their heads look huge bc their necks are so skinny. But they dont seem to be as handeable as GTPs. I still think i like atbs the best though.
I am biased but I say Ammies all the way! If you like the yellow coloring, there are solid reds, yellows, oranges, patterned varieties of each, as well as bi-colors and multi-colors. Mine is very handleable as long as I take her out on her perch and let her come off. And I like the oval body shape!