Thanks for the input. I've built a ridiculous prototype copy of the sweetcheeks for my Shineray x1. Method as follows:

Cut an old "bag-for-life" shopping bag. Sewn in space for 2litre pepsi bottles. Added some loops for trying down and : Works well for cruising, but slippery material isn't good for twisty roads or aggressive driving.

When I purchase my new bike I will try a mixture of a gel seat cushion and a sheepskin cover. If I feel the seat is too narrow, will make a higher quality, waterproof/slip-proof sweet cheeks rip off. Trial and error.
Just had an email reply from the seller of sweet cheeks and he is able to deliver them to China, so that's an option and the only option if anyone needs to widen up their dirt bike seat.