In our family, chopped herring was always served on cocktail rye slices, although my dad probably ate it on rye crisp. This year I tried it with rye melba, but it just wasn't right.
BTW, I just looked at a bunch of recipes online. None matched what my mom used to make. She used the jar of herring in wine sauce, not the salted fillets, and rye bread not white bread. It used to take her most of a day to make it, peeling all the apples, cutting the crust off the rye, and repeatedly chopping everything with a hand crank grinder.
These days I just put it all, including peels and crust, into a food processor and run until the consistency is right. Takes all of 5 minutes.