Hi and good luck with your project. I always have a soft spot for inventors.
Given the dimensions you mentioned, I would google for SLIMLINE stencils. They are like 2-4 inches wide and 8 plus long. They do come in layering sets-just add that to the search.
One thing you want to consider is the scale (size) of pattern. True there are stencils all over the place-Staples, etc. but those tend to be large ones for things like walls, furniture or t-shirts and seem too big to me? if you want tiny/small patterns, then yes, ones we use for cards would be desirable.
Even our stencils can have different scales which you will see. You may have to shift it and keep applying your color medium-which will be what? If paint, I would suggest water based so you can wash them immediately. You can always seal them to make them waterproof at the end. There are waterproof inks in the world as well.
Consider the size of a stencil...then study the pattern and see how often it repeats so you can gauge the size of the flower or whatever. A common size would be 6 x 6 inches. You can also just ask a mfg by email how tiny the individual flowers are. Craft companies are cool people and helpful.
You might want to practice with any cheap sale stencil on copy paper with the medium you want to use. Once you get comfortable with the idea and moving it around to extend the pattern, use a shipping box and go down a side, etc...then invest in the ones you really want.
I suggest you go to You Tube-which has a bazillion tutorials and ask to see
"How to use plastic stencils on cards" and then again with layered plastic stencils. (so you get the right size ones. I always find it so much easier to see a thing done than to try to read written directions.
These should get you started.
https://www.youtube.com/results?sear...ncils+on+cards
Also be aware not all plastic stencils are equal. Some are quite thin and delicate while others are more robust and durable. Also Europe can call a stencil a mask. Which is for us is the opposite. A shape you want to block off from your pattern or color. So stick to the US for now.
Hope this helps.
Locating stencils for painting
