General questions & Best Practices - Dual Instance, Layering, Multiple controllers

As a relative GP “newbie” I’d like to know some thoughts on the following. I love GP4, have been working very hard to get it together and so far, so good, but here are some questions. Maybe I can improve things and others can find the answers useful.
-My usage: LIVE only (for now) Church setting. 2 identical controllers - 1 at the organ console (which is old - non midi) the other next to a Clavinova about 15-20 ft away.
I’d like both controllers to access the same widgets/plug-ins by default.
I have multiple rack spaces - each with multiple PI’s that are orchestral in nature. eg. Strings (solo and ens), Woodwinds, Tonal perc & Bells, Brass, Plucked, and of course, Piano(s) and pads. I need access to a wide palette of sounds for any occasion.
I need the option to LAYER the pianos and pads with any other instrument on-the-fly… to conserve CPU power, I’ve put the piano’s and pads on a Global RkSpc, with widgets that control global parameters linked to the PI’s. I understand that RkSpcs can’t be “layered” per se, and I can’t but 4 different pianos and a bunch of pad PI’s on EACH RkSpc. Even still, I’m not totally comfortable putting all these PI’s on the Global. It can get confusing when edits have to be made on a linked parameter.
Question: Is it better, reliability and CPU usage, to do it this way or via a dual instance and if Dl Inst is better, can a widget from one instance control the 2nd instance?
Question: Can Rig Manager control the SAME parameter without utilizing hidden “linked” widgets? Because since there are only 26 links per RkSpc. On some, I have more widgets then there are available links!
I haven’t used GP Script and I’m a total newbie on that end of it (at least for now) so I have to shelve that option.
Sorry for the long question, but I redo my setup if I’m going to restructure my approach, and I’d rather do it now than later - when it’s gets more complicated. Thanks!!

Useful videos:

Multiple instances is also a stable solution (and CPU efficient) - [blog] How to use multiple instances in Gig Performer 4

Thanks npudar! , I really appreciate the links.