Plan-G and Downloads

[mikeody]

Hello All,
I am new to Plan - G but before I install it, given that it needs a 'live' internet connection -  I am keen to know what impact it may have on my monthly download allocation both initially and ongoing.
My limit is 4GB per month before the ISP 'shapes' down to snail speed but I need a fair chink of the 4GBs for other things.
Can anyone advise please.
Thanks.

[tim arnot]

Each map tile is 256 x 256. They are cached locally, but how many you download depends on how big your window is, how much you move/zoom around etc.