I think the pick & pluck foam trays are optimal for storing these non-standard shaped miniatures, and god knows there's quite a good chunk of them in this game, but I don't think it's optimal for storing a large amount of standard 1x1 miniatures. I would think a pre-cut standard foam for standard mini size would store a lot more than its pluck counterpart. The one I´ve been looking into buying stores 37 miniatures in standing position. That covers a good part of my collection, and they are inexpensive in comparison.
Maybe the best way is to use pre-cut trays for the standard shaped minis, and pluck trays for everything else?