2 1/2" at the heal is the most common dimension for a field or sporting clays gun. I believe the raised heel is for driven bird shooting although I have no experience in that area.
It is harder and more risky to bend a stock up or down than for cast off or on. I have succesfully bent a stock up an inch, half inch at a time, letting it set for a day and then another half inch. I have had small cracks develop during the bend. Fortunately, so far, they were small and repairable and almost not detectable, not going deep. I would be hesitant to take a chance on a really expensive gun.
English Walnut is known to bend easier than American Black Walnut, so wood type is a factor.