Having carrying a Glock 26 in my pocket many times, I can say that it is A LOT of gun to put in a pocket. It only works for me in the very big front pockets of my Columbia cargo shorts.
I have no experience with the Walther PPS.
Normally when I pocket carry, I use a KelTec P3AT. I will evaluate the KelTec PF9 when I get back to The World, though.