It would be nice to be able to combine the "projectscale quarterly" and within these quarters the monthly scale (like "projectsubscale monthly") shown.
(this should work for weekly + days within the week as well and monthly with the days as a subscale)
The zoom is probably best taken from the subscale as that would define the width of the projectscale.
I only see need for 1 level of subscale, but maybe it is easier to make it generic for N levels of subscales...
