Hey you've got some good armchair bow making to play with there.
Whacky idea... If you saw off the sap wood by setting your saw at the correct angle, you could maybe get two nice strips to use as backing.
So you could make a 'laminated self bow'.
I think you are right, the plank isn't thick enough to get an ELB out of the edges.
Step a way from the saw....
I can see you are going to have a happy new year with that.
Del
(Whaaaa... EDIT! I meant to say you ARE right!)