The Abe and Sons is the one. I have tried dozens and once you have mastered the calling techniques it sounds the best. It has an external call that sounds great but is removable. As for Carlton's, Im not sure if they purchased Abe and Son's design but it looks exacly the same. I do like the versatility of a mouth diaphram but the external diaphram on this call really sounds good.
Best of luck to ya. Practice practice practice and don't over call. Elk do have a language try to learn it. Elk nut on here has some pretty good stuff to check out. There are some tricks he does not expose, either he is saving the tricks or has not yet found them but from what I have seen and heard he is a very good place to start. If he does know them I hope he keeps it quiet.