Yes, I finishsed it last September. So far zero issues with power shedding but the real test will come this summer. I have a single Magnum 2000W PSW inverter and it does just fine. Here is a link to a forum doc that I uploaded, detailing my install.
I like your idea re: the transfer relay. I'll save that idea if I run into problems. All in all one of the best mods I've done to date.
Did you finish your Norcold replacement? I saw your query re EMS load shedding while searching for info on replacing the NoCold unit as I am doing right now. What did you do about the fact that residential fridges don't like quasi-sinewave power sources like the Dimension inverter I have on my Itasca. My power source for my new fridge will be a pure sinewave Xantrex inverter dedicated to the fridge but I want to power the fridge from shorepower when it is available so I'm also putting in a separate power transfer relay with input #1 being shore power and input #2 being the Xantrex inverter output. That leaves me yet to figure out where to pick up the shore-power source for Input #1. Right now I'm thinking I might just use the AC breaker output which feeds AC to the Dimensions inverter/charger.