Working with the pixel perfect camera

I'm working on a game with varying sprite sizes. A sprite might be 100x200 and another might be 25x40, etc.. Because of that I am not sure what the "pixels per unit" should be set to, some sources I've seen say it should be left default because it doesn't influence anything, some say it should be set to the size of all your sprites (for example, in a 16x16 game it should be 16, but I can't do that because I don't have a unified size), some even say it's all fine to leave it default (100) so long as all your sprites have empty space to make their sizes be multiples of 100, I don't know what to do. I want all my sprites to have the same pixel size, as well as to be able to make them snap from pixel to pixel on a lower res looking screen, this includes particles and otherwise higher res effects, which I want to be purposefully pixelated to achieve the effect, this latter part could be done by artificially lowering the resolution of the screen via script, however that would also cause the colors of the otherwise already perfectly sized sprites to smear and blur when inbetween pixels, which would be a nightmare, does anyone know what I should do or any good resources that could walk me through the process? Thanks in advance!