Straight up to your questions:
#1: The "space" you are referring to is left deliberately, because without it the user will not be able to double-click and create event on specific place. In general, it cannot be removed, but you can try to reduce the item height using CSS. Please note that custom implementations are not covered by the standard support services.
#2: You can use minorTickCount
option that defines how many delimiters should be added:
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