These pinch forms are made from Aardvark Papel porcelain Cone 5 paperclay. It was fired to Cone 5 from greenware without going through the bisque stage. Shrinkage is about 15%. This is just an approximation. I did not make any measurements but they sure came out a lot smaller than when they went it.
A one-fire process saves time and more importantly, energy, either gas or electricity, so it's environmentally friendlier. To me, ceramics has never been a "green" undertaking as so much energy is needed to convert the raw clay to something that is totally different from the starting material.
Depending on your paperclay project, a one-fire process may be applicable to you.