wild hens and jakes (yearling gobblers) make the best calls since the tone from them is a little higher and sharper, but do not throw away a gobbler's wingbones on that account. I have made several gobbler wing calls and they work well in the fall...just slow your rhythm a little and do two yelps, like a large and dominant tom would do.
And for that matter, if you carry a slate call, try using the mouthpiece of the wingbone call as your striker!
Sheesh, giving away my secrets for nothing, what am I thinking.