There are several photos of the West Oakland roundhouse in John Signor's "Southern Pacific's Western Division" book. A color photo of the roundhouse can be found in Tom Dill's "Southern Pacific's Historic Overland Route" book (by the way, the middle photo on pg. 13 of his "Southern Pacific's Colorful Shasta Route" is not the Oakland roundhouse but rather the San Jose roundhouse).

The still-standing roundhouse at Bayshore and the former roundhouses at West Oakland and Mission Bay all had the same basic design, so examining the Bayshore roundhouse or photos of it might be helpful.

Bruce Petty's/Steam Age Equipment Co's. "Southern Pacific Lines Common Standard Plans, Vol. 5" has plans for the roundhouse at Hazen, Nevada, which has a number of similarities with the West Oakland roundhouse, including the stall length (88 feet), the windows at the back of the stalls and apparently the size of the windows on the end walls. The major differences are the spacing of the windows on the end walls and some structural features on the end walls.
(to be continued)