Objects update time? (live push of data?)

Hi

I am looking at designing a few layouts, ive done alot of terminal designs before (not HomeSeer) which raises a questions.

Assuming i have 2 items, button and data field (see below):
Button [on / off] with images for each
TEXT [status tracking from a field in HomeSeer)

If the above button for on / off is on many remote screens (HS Touch), and one pushes it "ON", how long does it take for all the other screens to show this update and change there status to ON (with the correct related image)?

Same question for the status tracking field....

Many Thanks
Ashley