The smallest size is a garklein. I've got one (wooden, made by György Bán in Budapest) and can just play it, though I need to keep in practice - there is no room to spare at all. (I have average-sized hands).

soprano = descant, alto = treble.

Another trick to supporting a tenor: cross your legs with one foot on the other knee and sit the end of the recorder on that foot. (I have on one occasion started to do that when wearing a kilt - oops).

A neckstrap doesn't usually take the weight in a useful place, but good luck with it if it works for you.