That Defiance is a very pretty machine. It's a later model than mine, and made after the name change to National. I was specifically after a machine made before the name change.
And the good news - my tucker fits! The bed hole in this machine is in a slightly different location than the National made machine, and it's also a different thread.
But see - it fits!
When I put this on the newer machine, the needle came down smack on top of the tucker bar. This one comes down just in front of the tucker - and it's the needle clamp that does the "pressing".
I was wondering about that extra leverl looking bar in the front, but it fits to hold the front guide firmly against the machine.