Questions about Individual Investors (I will not promote)

Gonna be a bit vague on the industry because it’s super tiny, but I’ve been running my own service business for about 4 years now and make a modest living. Initial funding was from a credit union and I have complete ownership of the company. I’m looking to expand into manufacturing within this industry because there are niches that are entirely unfilled and would vastly improve revenue on the service side IF I am successful. That being said, I do not have the cash on hand to pursue the goals of manufacturing/hiring specific engineers. I already know some wealthier individuals who I can approach for investment, but what I’m wondering is when dealing with individual investors, how do you go about figuring out how to structure ownership/shares of the company when pitching the idea? Like do you offer a percentage of on profit, do you offer a percentage of ownership, what does it look like in terms of company structure? Would I setup a separate LCC and have proportional ownership with the investors where we all share in the gains/losses? If setting up a separate LLC, how would you go about adding additional investors later down the line if necessary? Would filing as an S-Corp or something other than an LLC be better for that? I know there’s multiple ways to go about it, I just need ideas for what’s worked in the past for folks who have dealt with investors. I want to keep majority ownership if that’s possible, but at the same time I do not have the capital to match what I need to get this part of the business up and running. I also want to avoid loans because I would like to avoid bankruptcy. Thoughts or additional resources are appreciated.