Multi part mold fasteners

I’m wondering what different methods there are for fastening multi part molds together. I understand some people use rivet nuts, so I have been searching for a kit to buy. There are so many different types of rivets and guns available, so do you have any recommendations?

The tooling should have built-in locators, and fasteners can be simple nuts and bolts with fender washers. Fasteners should be staggered instead of in a straight line.