I don’t know what water-slide paper is, but there are lots of printable adhesive papers… and a layer of clear glossy adhesive vinyl to drop on top might look good too
I have used a similar water-slide decal on several prototypes, and it works like a charm. Can’t say for the one you have found, but looks like it’s quite similar to the one I used. Can’t remember the brand right now. Works best if you give it a clear coat after you have applied it and it has dried.
I think I might have missed that this was going to be for a model, like the water-slide decals for model airplanes…
you might want to look into “rub-downs” transfer film. They are what most modelshops use when they don’t pad-print or screen. Modelshops will have a good source
Travisimo is correct – rub-downs are the best way to do it. Google the following: rub down transfers, dry transfers, cromatecs, INT’s and you should be able to find someone in your area that produces them. There are several places on the web. Usually 24 hour turn around in any Pantone color or foils – $90 to $125 per sheet per color and you can gang many colors on the same sheet, registered in position and you can jam pack as much on the sheet as you can. Just keep in mind that there is a certain fragility to transfers, they are not permanent, they are easily damaged.
I was once the Jr Designer applying the dry transfer rub downs to keyboard keys… not a fun job, but they seemed to go on fine within tight spaces. A layer of clear polyurethane spay will almost permanently seal them down so they won’t easy rub off…
That looks like a fun machine Sam, lots of interesting one off sticker potential…