I prefer to go as light as possible, this way you don't sweat so much when moving and may not get as cold as you otherwise would when you stop - it's all about layering correctly ie, if you find a fleece too hot, try thin thermals?? I reckon shorts are a big no tho as they wont really conserve any heat at all! If you going down the light weight option try a few things out and see how they work for you and until your happy or dont know the system always take spares for when you stop. (a cheap waterproof works very well for this). Going lighter-weight in clothing will give you a more comfortable trip.