I think I can answer this one!

The Simple Series - 12-15 inches from the base of the body to the top of the head (depending on the headshape). The Pinhead Puppet stands the tallest; The Glorified Sock Puppet is the shortest. When it comes to the Simple Series Patterns...think "Prairie Dawn" or "Roosevelt Franklin" in terms of size.
The Forma Series - 15-18 inches from the base of the body to the top of the head. Again, the Punto Puppet would be on the tall end of that range. The Forma puppets are more "normal" in size, more in line with your "average" puppet made for screen or live performance in terms of size.
The Monster Series - The Mostro Puppet stands 25 inches from head to foot, and about 18 inches without the optional legs. The Borsa is 25 inches from the top of the head to the base of the body. One great thing about the Monster Series, really all three pattern series, is that the puppet parts are designed to be modular. For example, you can use the Borsa head on the Mostro body and vice versa without having to alter either pattern. So from two patterns you actually have four different shape configurations.
One more thing that I always mention when folks ask about the size of the Project Puppet patterns is that in puppet design, small is good. The size of an average human hand and arm doesn't vary that much, and you want the puppet to fit that hand and arm. The better the fit, the more control the puppeteer has, and in turn the better the performance (potentially). Bigger (although it may be necessary for some characters and will bring its own design challenges) is not better.
Hope that answers it!