What you have in mind is called bucking. THe Garret Wade saw looks more like it is for crosscutting dimensional lumber, not thick logs regardless of what th etext says.
I bought a 4' replacement bow saw blade from a home center and made my own bucking (bow) saw out of wood. THe problem I have always had with the steel bow saws is that the frame isn't springy enough to keep the blade taught.
I'd suggest the crossctu saw from the crosscut saw company. I have had no experience iwth them, but they at least LOOk like the right kind of saw. I know a few people who hav ebought Garret Wade saws and they were not favorably impressed.
Best bet would be to buy an antique and tune it up.
Let us know what you choose and how it works.