Hi Goldleaf,
As far as I know, the waigong aspect of this art does not require additional workshops. There is, however, more material to be learned in China if you wish; the neigong or "internal training" of the system.
Grady has indeed taught this method several times before in the US. If you are after tangible results, Yijinjing Gengmenpai training will certainly yield them if you put in the work.
Please have a look at a few of Shifu's youtube videos as they will give you a better feel for the art than I can;
https://www.youtube.com/channel/UCQMM7M_0SWmlgS6NBLES2ow