[a brief thread-necromancy] For anyone needing this in the future, I had his workshop 'acquired' by Pemberton Industries five years before the start of the adventure, after Grappa's disappearance from Risur. It was located in what is now referred to as the Pemberton Industries Office Building mentioned in the Pardwight university buildings (page 16, Cauldron-born).
My personal canon: after returning from the Third Yerasol War with his intentions as laid out in "I, Grappa" (page 3, Cauldron-born), Grappa needed resources for his passion project and hired on with Pemberton Industries. While he worked for the company by day, at night he made use of their laboratory space to pursue his own projects. He was eventually discovered and, rather than punished, commended for his ideas and promoted. For better or worse, this is how he came to the attention of the Ob. After being recruited, he disappeared from Risur, and Pemberton Industries inherited his designs, patents, etc.
I feel Grappa's mind-making being partially stolen by Pemberton dovetails nicely with Pemberton's newer mind-magic interface shown off at the arms fair, his B.E.A.R., and later, his duplicants.