I've planned holiday in london, i'll arrive sunday in the afternoon to
stratford and i need to buy a travelcard. I've checked ticket office
opening hours but i don't know what's the difference between main and
jubiliee (http://tinyurl.com/cylr5g).
I'd also like to know how busy is the jubilee line during the week at 9
o'clock, is it hard to find a seat goind toward backer street?

Thanks in advance