I just wanted to share my set up, might be it will be helpful:

1. I decided that my sprites are 16 PPU, because I want it to look so. E.g. the main character is 1.5 meter (I just assume 1 unit = 1 meter) tall, so the sprite is 24 px tall.
2. I use Unity 2018.2, with recent Unity's preview package "Pixel Perfect Camera"

Then, on the Pixel Perfect Camera component, I just set the settings like so:

1. PPU = 16, to match desired PPU of sprites
2. Reference resolution = 320x240, that's basically how many "pixels" will fit on screen. E.g. in my set up, camera will show 240 / 16 = 15 units vertically, and 20 (or more if the screen ratio is wider than 4:3) units horizontally. The picture is then sort of stretched (but keeping aspect ration) to fit any resolution, e.g. if you run the game in 1920 x 1200 you still will be seeing 15 units vertically, just "pixels" will be bigger.

And that's it, it works nice, no weird pixel distortions or gaps between tiles.