It's easy when you know how Michel😉
But now you see what I meant in our PM exchange-
You have very little freeboard to play with to make her RC sailing capable!
Even if you add pontoon like ballast tanks or a keel-weight of some sort to improve stability, i.e. wind / wave resistance, you will have to be very very careful not to use up that freeboard and then some😮
Either way she will always be a millpond / dead calm only sailer.
Keep the top-weight as low as possible and make sure that the deck, coamings for the superstructure, and doors and windows on the main deck are absolutely watertight, cos I expect that the smallest ripple on the pond would seem like a two metre wave to her and wash over her decks. I think I would probably glue and seal the main deck superstructure to the deck and make the upper decks detachable for access to the inner workings.
Your biggest problem is going to be finding the compromise between stability and riding to her correct waterline after fitting the RC gear, i.e. keep the 'fittings' as small and light as possible.
With that in mind the sort of kit that we Plastic Magic maniacs use may be your best bet.
I (and others on this forum, like the guy who motorised his magnificent Tamiya HMS Prince of Wales) can maybe give you some tips and sources for such mini/micro kit.
Good luck🤞, Doug