With the extra keys, you can have 4 modifiers on each side of the space bar: Control, Win (Super), Alt and Cmd - total 8 modifiers, ideal for your thumbs! This

With the extra keys, you can have 4 modifiers on each side of the space bar: Control, Win (Super), Alt and Cmd - total 8 modifiers, ideal for your thumbs! This still leaves you with the Yen and the Ro key to map for other things!