...Trim to JJ is something you use when it is beneficial, and not when it isn't ... How about that!!!! ????
I think it's pretty well known in GUE circles that JJ is a fun guy to dive with, and isn't a stickler for perfection outside of where it's necessary, although I have never had the privilege of diving with him. However, I have seen many videos of him diving. Even today's GUE Fundamentals class videos include probably 20 year old demos by JJ, and I honestly think that the "GUE perfect trim" with hyperextended neck, face forward, hands in front not down, hyperextended back, and knees that never drop that Dan alluded to doesn't come from JJ himself, at least not back then. GUE instructors have said that trim should follow the slope of where you're diving. If you're diving an incline, for example, it's ok to be "off-trim". Look at the GUE standards of trim being within 30° and buoyancy within 5 feet of a target depth for a recreational pass - far from perfect.
The person that I hear that inspired the above level of trim and control was Bob Sherwood. Until Dan called it the GUE position, I always heard it called the "Bob Sherwood position". I don't think many GUE instructors dove in that precise position originally, but more of them do now. In fact, I have had DIR divers on boats in the US tell me that I "must have been trained by Bob Sherwood" without knowing anything about me except seeing my equipment configuration and position in the water.
While Bob is usually absolutely effortlessly perfect in the water, when he's not teaching but just diving for fun, he often goofs around, goes a little out of trim, turns onto his back and blows rings while we're doing minimum deco, and generally just has fun. I have broken the seal on my mask by laughing many times with GUE divers, some of them dancing and even singing u/w.
This pic is from 2013, shortly before I took Fundies. I was taking a ride on the human DPV, Bob, and he turned his GoPro onto us.