So, Willie said this design wouldn't have survived as a 55 anyway. Can you tell me why? What do I need to do differently (other than not putting a hinge in it 
) so I can up the weight on my next one?
sight down the resting bow and see if the set you have was taken locally in the area you had trouble with, or whether there is also some set taken over all. try to judge how much is in the limb that was more trouble free. Maybe trace the good limb and flip the bow and trace the good limb again to get an idea of your woods capabilities.
Each piece of wood is different, and setting a tillering weight goal in advance is an acquired skill.
Tracing the back profile
as you go is a good way to monitor set. If it early on as the bow is drawn further, then more thinning and lowering your weight goal is in order. Finishing out with an inch or so of set is not bad, but you should see it appear in the last few inches before reaching design draw weight. by careful monitoring as you go, you should be able to see
just unstrung set return to a straighter profile as the bow is rested.
Having some sort of backstop behind your tiller tree lets you reference previous marks after making a pull.
If you want to hit an exact weight, you can go wider, shoot for a higher weight goal then you prefer, and narrow the limbs some if the bow is coming in too heavy without taking set.
