thinking 20 \ 10 will be too small for me...as i will be taking clothes, trainers, waterproofs, tools, spare visor etc... So maybe a US30, and a US10 and maybe the R25 rucksack too...
I used to use 2xUS10 and 1xUS20 and put 1 trainer in each of the US10s. Spare visor I carried around my waist as well as my spare tyre
I bought a set of dry sack waterproof bags from Tesco direct.There are three sizes in the pack,with roll tops to keep stuff dry.I used them on a trip to Portimao & they were brill,I had them on the rear seat fastened down with bungees.Only 8 pounds for three,result.
You know what they say pack it all, then unpack it and leave half of it out. It may be worth looking at light/compact clothing etc it makes a huge difference, for instance jeans are so bulky and heavy, as are some shoes too. This was for a 2 1/2 week trip to Portugal in October, so I had more layers in there than a normal summer trip, water proofs, cable lock and a netbook etc. Next time I will be using one of these, they are so stable and keep the weight lower. http://www.ebay.co.uk/itm/Jofama-Ba...s_Other_Off_Road_Clothing&hash=item5d4ba91ec0