From the pile of luxury issues:

In the available screenshots of the properties window I see that thirtyseconds of a space get converted to the most simple fraction (16/32 to 1/2, 8/32 to 1/4, et cetera). Might there be some toggle on some options page that would allow to show such values strictly as thirtyseconds?

Also, I noticed in another thread that Daniel referred to setting stave size by a quadruple of the height of a space, which, while technically just as correct, is a bit odd, considering that for staves there is the traditional unit of… well… Stave Size (in millimeters). Is such linking of Stave Size directly to Space Height by design, and if so, what is the rationale behind it?

Our rational spin box always tries to find the lowest common denominator for the current value. The up and down paddles increment and decrement by 1/8 space, while Shift-clicking increments and decrements by a whole space. We do not currently have the option to retain the current denominator when adjusting the values.

Since the space is the key measurement in music typesetting, from which all else flows, I think it makes perfect sense to define it explicitly. At the moment the read-out in the Layout Options dialog that tells you what the effective stave size will be does not update dynamically when the space size is changed, but this will be done in due time. The default 5pt space size gives, of course, a 20pt stave, or just a tiny, tiny fraction over 7mm.