When you first joined and asked what people looked for in a slingshot, I suggested that it be something effective, but also elegant and well finished. I agree with what harpersgrace said, if someone looks at a board cut and reckons they can make it in a short amount of time, they won't buy it. This applies to a lot of things, but slingshots seem to attract a crowd of people that are good with their hands. You need to be especially innovative, creative or skilled to pull something off that the members here won't feel ready to replicate. You can't compete on price, either. $30-50 may be the going rate for a handcrafted slingshot, but even if you cut your labour to zero and just charge materials, consumables and postage then the difference won't be that great. It may even be more than what you can buy a Saunders Hawk, or a finely handcrafted Chinese slingshot for.
I admire that you're going about this like a business, even if you're just two kids cutting boards on weekends. If I was a business advisor, I'd tell your departments the following:
- Marketing: Position your product in an under-served niche because your production capacity and price and quality competitive advantages are low.
- CEO: Maximise your return on resources. Identify where the greatest value added and greatest resources are and focus on that. Look to the future, but in a startup focus on getting a good first product to market. Make sure all corporate structuring, procedures are in place and liability is mitigated.
- R&D: Quickly settle on a winning form and stick to it. Spending resources on development saps your ability to actually do business.
- Operations: Look at the production process and where it needs to be more efficient. Use templates, produce in batches, reduce waste.
- Finance: Make sure you have sufficient funds for start-up, capital expenditure on equipment, and cover working capital for materials and inventory. If money is tight, borrow others' resources and focus on reducing working capital tied up.
- Purchasing: Can you buy materials in quantity, or find other buyers to split larger orders? Are you buying from the most cost efficient source?
Take the T1 for example. This was my thought process: I noticed very few people were working with plastics and laminates and wanted to promote new ideas about new materials. I can cast resins, but not many people want to do that and it doesn't showcase workmanship well. Board cuts on the other hand can make use of strong sheet cast plastics and fibre reinforced resins. Board cuts are also fast to produce and shoot well. The problem was they usually have to be very thick or they don't feel right in the hand. Modern laminates don't require such thickness for sufficient strength. I developed the T1 to be a thin board cut target shooter. At the time, I was spending a lot of time on new designs but I don't really want to give prototypes away. Sometimes it's because there's things that aren't quite right and I don't want it tarnishing my reputation, other times it's just perfect and I don't want to give up my best working example. I settled on the T1 as a template because it had proven itself and I planned to make lots of them. I have given no other design a template number because they are intended as one-offs, at least for now. The T1 however would make a great trade item so that I can get them into as many hands as possible, get detailed feedback and trade for other people's work without spending a lot of cash. I have considered lots of ways of making them faster. I'd look at CNC or outsourced hand cutting, but for now production numbers are best served doing it in-house. The slowest step is accurately radiusing the edges and I'm on the lookout for router bits. I have now settled on using paper micarta as the board. It's cheaper, kinder on tools and faster to cut than G10, stronger than acrylic, more rigid than polycarbonate, more plentiful than exotic wood and doesn't get into my skin, lungs and eyes. I have several square feet bought from a stockist's offcut bin and they're all scribed out ready to cut. The design tessellates quite tightly into the board widths I picked out of the offcut bin. I have all the resources needed to complete these boards already to hand. The key now is to crack on and focus on fit and finish and quality control.
Back to your original question, I haven't received your slingshot yet so I don't have any detailed comments. I prefer your left-most design. #3 is prettier, but the design is weak at the base of the forks where the grain is also weakest. Safety has to be your top priority. We (especially Americans) live in a litigious society and if you have been holding yourself out as a business, and somebody loses an eye, then you may well be treated as a business by the courts. They'd probably find you to be proprietors of an unregistered business without a limited liability structure and lacking product liability insurance, so you or your parents might be held financially accountable to direct, derivative and punitive damages. BTW, do you need CE or other markings to be selling a product in the relevant jurisdictions? I don't know.
Like Bill says, I'd also like to see better pictures of your slingshots before I can comment on fit and finish. I imagine that if a few of us commented similarly, then your potential customers won't have enough detail to decide on making a purchase. Big-name makers with a reputation for quality may get away with it, but newcomers like you and I can't. I always wait for good light and take sharp and detailed photos to post when I showcase new slingshots.