I don't know if the float test works with walnuts. It very well could; I just don't know. It would be educational to see a floater cracked open to see if it is viable or not.
But your walnuts' moisture content is certainly fine. they couldn't have dried in so little time, and you don't need to dig them up. They are either going to grow, or they are not.
Where possible, like a paper towel, Daisy is right, you will want to keep seeds separated and as far from each other as is possible. If one becomes diseased and it is close to another, the disease will spread that much quicker. When you are checking the progress of your seeds, it is important to remove anything you find dead and molding if you can. In the case of my Jeffersonia seed, it is an impossible task.
When seeds are going through a pregermination treatment, like cold conditioning for your maple seeds, distancing is not important. Until they actually germinate, seeds should remain "sealed" within the seedcoat and virtually untouched by disease. They can be all jumbled inside a bag with a moist (not wet) media. When it is time for them to germinate, that's when it's best to have them separated.
So if you do all this the easy way (way, way easier), and plant them up once in a pot with potting mix as Daisy suggests in the last paragraph in the previous post, you will want to distance them right then.