Given the nature of this forum, I thought this was an, um, interesting article...
http://www.theregister.co.uk/2007/04/23/crow_masterplan/

She would gawk at how much we go through-I love my wipes! But my daughters often forget to flush the toilet so we are at least conserving water!

One square? That could be, well, messy...

i guess it all depends on how mess your dump is!
i tend to try to dump in the morning before i shower so i can usually use one square and then make sure everything is clean in the shower.
but in the evening, if i have a bonus dump, i tend to use two squares and sometimes 3 to get super clean as i tend to not like to shower again in the evening because i get chilly sleeping :-)