Correct superdav, I was referring to the thickness of the limb. Also if the stave is 2" wide and you want to 1 &3/4" limbs leave it the full 2" width at the point of the knot as well, for the moment.
A knot that runs across/through the limb side to side is tricky and potentially much more dangerous than one that runs back to belly. (Usually only get them using a quarter sawn board, not when using the growth ring on the back.
I don't know if your knot is just the stub of a small branch that got covered up(most likely), or does it come out somewhere on the belly?
If its just a stub you can start carefully drilling/digging it out with the point of a sturdy knife, see how far it goes in.
Post some more photo's as you go, if you're still having trouble on what to do.