ERC backed with hickory bows are tempermental to build. Generally speaking, I often end up with a 40 pounder when I was seeking 50-55. With a 2" reflex, you will get an early illusion that there is a need to remove a bunch of wood as it will seem quite heavy to draw in the long string stage. Once you get the tips bending 6" evenly tillering should be with great care and hesitance to remove wood. When final tillering is req'd, put all of your files, rasps, and drawshaves away. Sandpaper and scrapers is all you will need to make tiller adjustments. Do not rough out your stave to 64". Start long, say 68 inches. Invariably, you will over tiller and end up with light poundage. The extra length will give you the ability to shorten the bow which will gain pounds back for you, provided your tiller is still good. Also, I would go not thicker than 1/8 inch on your hickory backing. ERC tends to fret or chrysal on me. Sometimes it will change the tiller and you will find yourself see-sawing your way into a light bow with tiny corrections. If the fret isn't too bad, just live with it. Also, your backing should be as flawless as possible. 50-55 pounders seem to stress the back quite a bit. Any small pin knots on the hickory may tend to fail.
On the other hand, ERC/hickory backed bows are very quick in cast and beautiful when finished. I don't intend to frighten you but just to caution you. Whenever you feel the itch to hurry it along, get a bucket of water out and dip your head in it.
Good Luck!