Used my voucher to fly my inlaws here for the Easter holiday. I used the "Availability Tool v1.61" to search for E seats - and give or take a day, found what I wanted on non-stops for travel around the holidays. E wasn't available on all flights, but we had a bunch to select

Our search was more limited that we also needed to find an N (Y award seat) on the same flights. As luck would have it, it seems that E and N were pretty highly correlated in terms of availability.