People produce very low volumes of poo! The average is around 300g/day and most of that is water (around 80%) with the balance being mostly poorly digested food and bacteria. A 20L solids bucket can last one person up to around 40 days, two people 20 days and so on. Whilst toilet paper can be added into the solids bucket it can dramatically reduce bucket fill time so, if you can, separately bag the paper and bin or burn. Perhaps allow guests to put paper in the solids bucket as ‘binning’ it may be one step too far 🙂