If you're using wool outers (eg. the Disana pull-ups) we recommend a woollen outerlayer too. This continues the breathing/wicking process and is much slower to get wet than cotton. A good example is the Disana dungarees below or the Merino wool trousers/leggins in the section above.
All the dungarees here are tried-and-tested over cloth nappies. Feedback very welcome though!