Both the Rad Map and Rad Image components let you set a date and hour range ... check the hidden inputs ('+" button on zooming in).
My bad, I had no idea, but makes sense!
Just to be sure, it's not possible to set the hidden parameters via Grasshopper inputs, right?
(I don't think it's necessary, though. Certainly beats the Honeybee user interface in terms of reducing complexity IMHO)
Clicking on the parameter in the dropdown should expose it as an input.
Cool, even better!