It's been a number of months with this little guy in my mixed tank and wanted to report back for others that may be interested. So far it's still alive and I don't have any gorg. It's been mainly feeding on GSP and I know that because while it roams, it will always return back to the GSP islands. Also I have a GSP rock that is on the far side of the tank which it has not found yet. When comparing the 2 islands I noticed the polyp lengths between the two to be significantly different suggesting that it's eating. It isn't eating the underlying purple mat, but just the polyps.
I was experimenting if it will keep GSP under control: It's not killing it off, but does keep it short. And yes GSP seems to be an acceptable food source for those that want to keep one. Alive for 3 months...so far so good.