I think our parish has this well under control. We have a center aisle, two side aisles, and two wall aisles. There are two MHCs for the Hosts at the head of each of the two side aisles (four altogether), and four MHCs for the Cup, two (facing opposite directions) at the center aisle, and one at each of the wall aisles. People come up the side aisles in two rows to receive the hosts, and then they split toward the center and wall aisles, receive from the Cup (or not), and return to their seats. The portion of the eight MHCs are Es depends on how many priests and deacons there are at any given Mass. There is always at least one ordained man at the head each of the side aisles, and whenever someone comes forward in either of the lines with crossed arms (or a babe in arms), he takes care of the blessing. Things are done decently and in order.