I don´t understand the panic.
If you want to change the wheels, take wheels from an other bike and fit them into the 961.
No difficult job for a workshop.
If you want spoke wheels, you can use from some japanese bikes.
You can use also alloy wheels from other brands.
I have Moto Morini wheels in one of my Harely Davidson.
The Kineo wheels are expensive and not really nice, but they work are tubeless and they fit 1 to 1.
If you don´t want to fit wheels from other bikes, you can only use wheels which are made for the 961.
To fit wheels from other brands can use several hours to make all the spacers and so on, but it will work also.