General widget sizing

[Sting]

My question is more general but I will use the table or list widget as an example to talk about.  I want my UI to be clean, there is only so much space on the display.  What I want is to make the table or list widget a specific number of rows tall.  Currently the height is governed by the number of pixels at creation time.  But, only the developer knows how tall the title or the headers are for the table widget, so it is nearly impossible to get the device to look clean.  And only the developer knows how high the row is because of row padding.  How is this expected to be handled in the development process.  Is this expected to be available in the documentation.   Should it be added to the documentation block for the create function?