Hi - got my new bike this week after having the other one stolen and am starting to get it ready for my 3week tour across Japan. Its an 08 Dr Dew and it looks mint! However it came with some chunky conti tyres which are slowing me down a tad. I took the forums advice and will get some Schwalbe Marathon Plus tyres but which size do you plump for? For touring i need some comfort but also want a fast tyre. Options are 700 x 25/28/32. Thoughts?