I'd start by adding rods that will be far from what you already own. In other words, have big gaps in depth achieved. So if it were me, I'd go with a 5 color or 300' of 45lb copper.
The new giant 44's pull like a dream. They plane much further out to the sides of the boat with a load of core or copper than a walleye board ever will. For anyone that is considering trying them, I highly recommend you do!