Rushton Indian Girl

I'm rebuilding a Rushton Indian Girl and I've got a few questions (actually more than a few). I've redone a few Old Towns but I'm a little intimidated by this one. 1. The curved ash decks were sawed that way, not bent. Any suggestions as to how best to do this? Id like to get it out of a piece of 5/4 wood if possible. 2. In attaching a new inwale should I remove the brittle topmost plank before tacking the ribs to the inwale as was originally done? Or can I just tack through the planks , similar to the way the screws do? Thanks in advance. Probably more questions to follow.