Business or tourist visa

So you want to visit some business prospects; all you have to show is your normal requirements for a visa; which you are well familiar with as you have applied before.

The only reason you would show your new business documents is when you are fully employed there and are using that to show compelling ties.

You already fill that requirement by showing a letter of leave from work; a steady job, income from your current employer, etc.

The purpose of your visit is to attend business meetings, but that doesn't mean that you are going on behalf of a business or anything like that.

I often travel to Schengen to attend conferences, and this is also considered "business" but all the requirements are the same as a normal visit; the only difference is that I have an invitation letter from the conference organizers.

I think you are assuming that a visa purpose as "business" must have to do with work; which is not correct. A "business" visa covers anything not normally done as tourist (or other visa types, such as transit). It often means you are visiting businesses in the Schengen zone, but it doesn't mean you are traveling on behalf of your current employer.

You start by saying you have a business plan to meet businesses. It really and truly sounds like the primary purpose of your trip is to conduct, well, business. As such, you should apply for a business visa.

I know that's not the answer you want to hear, but "should I apply for a business visa when I'm going on a business trip?" is really more of an exercise in wishful thinking than a question. Lying to immigration officials is a bad idea. If you are caught, you jeopardize your ability to ever get a visa again, among other possible consequences. If you are singled out for scrutiny at immigration, you can expect them to ask questions about the purpose of your visit, and they are unlikely to be amused if they find evidence that contradicts your story, such as calendar appointments on your phone for business meetings or business materials in your luggage.

Nobody can say how likely it is that you'd be caught out in your lie, but the proper way to handle this is to apply for a business visa. If you cannot supply the required documents yet, you'll need to wait until you can do so (perhaps conducting meetings over video chat in the meantime) or go ahead and apply anyway, explaining that your business is new and providing as much evidence as you can to support your credibility.

Tourist visa. You've already got a tourist visa before so best to apply for it again. They have no way of knowing if you use the visa to meet your business partners.