I'd rather not get into that whole "it's not the size of the rhizome, it's the magic that it performs" thing, but just saying that this concern about the Size of rhizomes is really not a big issue. Most folks who have grown 'things' for a while, realize that if there is a healthy looking bud on a on a plant part, there's a good chance that it will grow. A more important consideration would be the general 'condition' of the rhizome. As long as it's not wilted/shriveled and looks healthy it has just as good of a chance to produce a nice plant as the next one. And your rhizomes look fine! Get to it!