Firun,
The choice of a model to do is not easy and there's always a risk.
If you have a doubt about a subject, you still can make a survey on your website.
Second option, produce a kit through a subscription.
I made this some years ago for a 1/18 decal project.
I was not sure to sell all decals, so I asked to customer interested to subscribe.
At this time, I needed at least 30 customers to launch the project.
They sent me their payment and I produced the decals.
Inconvenience : Customers must to be in complete confidence to send a payment and wait several month to get their kit.