George:
More than anything, my bunker style depends on what looks right on the ground, and also which of my crew actually does the bunker shaping. At Stonewall, Gil Hanse built nearly all of the bunkers on the Old course [with a bulldozer], while on the North course, Kye Goalby and Bruce Hepner and Kyle Franz built the majority of the bunkers [with excavators, which makes a big difference in what you can shape, too].
The similarity to a California-style bunker look is deliberate; the similarity to Pasatiempo is mostly an accident. Kye has done some of the restoration work at Pasatiempo with Jim Urbina, but Jim and Eric Iverson and Brian Slawnik were all working on The Rawls Course in Texas at the same time we were building Stonewall (North).