My condolences, Half-eye. Every broken bow makes us stronger though, right? (I'll try to remember to tell myself next time)
The two raised ridges left must have been under incredible amounts of tension! Deepening the groove would only be removing wood from the neutral plane-- wood that does nothing except glue the back to the belly. Wood that's not in either tension or compression. I wonder if the groove in the bow you copied was a channel for a cord back? I think a shallow groove would be fine, but the depth should remain constant. When you were tillering the tips, probably the ridges should have been thinned at the same rate as the groove. ...but then you've got runout... If anybody can make it work, it's you.
Can't wait to follow the next adventure!
Garett