I believe the information on the other forum may be wrong.
The P&A shows the following:
4-Point Docking Hardware Kit - Chrome
The ideal choice for maximum versatility, this complete kit contains the docking hardware necessary to install all Detachable accessory options. Even if you only install a passenger backrest today, this kit allows you to add additional accessories as your touring demands change. Provides docking points to allow installation of Detachable Sissy Bar, Solo Luggage Rack, 2-Up Luggage Rack, Solo Tour-Pak® Rack or 2-Up Tour-Pak® Rack.
54205-09
Fits '09-later FLHR, FLHRC, FLHT, FLHX, FLTR, and FLTRX, FLHRSE5, FLHXSE/2/3, FLTRSE3 and FLTRXSE/2 models. For use with Detachable Sissy Bars, Solo Luggage Racks, 2-Up Luggage Racks, Solo Tour-Pak® Rack and 2-Up Tour-Pak® Rack. FLHRC models require separate purchase of Saddlebag Hinge Stop P/N 90580-09.els require separate purchase of Saddlebag Hinge Stop P/N 90580-09.
The P&A also offers a CVO RK style backrest pad for the chopped tourpak. I don't think there'd be any interference.