Bob:
Sorry for the tardy post, but Ken is correct. The plate you have is designed for the single stage presses from MEC. I am not aware of a different plate designed for any of the progressive MECs. That said, one could make their own plate. On a progressive press you would need a plate to cover all but the priming the station (a MEC 650) or all but the collet and priming stations on those with collet resizers. (9000s and grabbers, etc...) You would also need a shorter main spring to allow for the 1/4" plate to fit. You may need to adjust your final crimp station as well.
Or (Option B) you can just leave your progressive press as is and simply load 2 3/4" once fired hulls trimmed down to 2 9/16" with 2 3/4" load data and simply add an overshot card prior to crimping the shells. No changes needed to the press or recipe. They are not as pretty as roll crimps, but they work just effectively without adding noticeable increases in pressure over a standard fold crimp.
Option B is what I prefer when reloading on my progressive presses.
